I am trying to create a simple user control that is a slider.  When I add a AjaxToolkit SliderExtender to the user control I get this (*&amp;$#()@# error:


    Server Error in &#39;/&#39; Application. The Controls collection cannot be modified because the control contains code blocks (i.e. `&lt;% ... %&gt;`). Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
    
    Exception Details: System.Web.HttpException: The Controls collection cannot be modified because the control contains code blocks (i.e. `&lt;% ... %&gt;`).
    
    Source Error:
    
    An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
    
    Stack Trace:
    
    [HttpException (0x80004005): The Controls collection cannot be modified because the control contains code blocks (i.e. `&lt;% ... %&gt;`).]    System.Web.UI.ControlCollection.Add(Control child) +8677431    AjaxControlToolkit.ScriptObjectBuilder.RegisterCssReferences(Control control) in d:\E\AjaxTk-AjaxControlToolkit\Release\AjaxControlToolkit\ExtenderBase\ScriptObjectBuilder.cs:293 AjaxControlToolkit.ExtenderControlBase.OnLoad(EventArgs e) in d:\E\AjaxTk-AjaxControlToolkit\Release\AjaxControlToolkit\ExtenderBase\ExtenderControlBase.cs:306 System.Web.UI.Control.LoadRecursive()
    +50    System.Web.UI.Control.LoadRecursive()
    +141    System.Web.UI.Control.LoadRecursive()
    +141    System.Web.UI.Control.LoadRecursive()
    +141    System.Web.UI.Control.LoadRecursive()             
    +141    System.Web.UI.Control.LoadRecursive()
    +141    System.Web.UI.Control.LoadRecursive()
    +141    System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627
    
    
    Version Information: Microsoft .NET Framework Version:2.0.50727.3074; ASP.NET Version:2.0.50727.3074

I have tried putting a placeholder in the user control and adding the textbox and slider extender to the placeholder programmatically and I still get the error.

Here is the simple code:

    &lt;table cellpadding=&quot;0&quot; cellspacing=&quot;0&quot; style=&quot;width:100%&quot;&gt;
        &lt;tbody&gt;
            &lt;tr&gt;
                &lt;td&gt;&lt;/td&gt;
                &lt;td&gt;
                    &lt;asp:Label ID=&quot;lblMaxValue&quot; runat=&quot;server&quot; Text=&quot;Maximum&quot; CssClass=&quot;float_right&quot; /&gt;
                    &lt;asp:Label ID=&quot;lblMinValue&quot; runat=&quot;server&quot; Text=&quot;Minimum&quot; /&gt;
                &lt;/td&gt;
            &lt;/tr&gt;
            &lt;tr&gt;
                &lt;td style=&quot;width:60%;&quot;&gt;
                    &lt;asp:CheckBox ID=&quot;chkOn&quot; runat=&quot;server&quot; /&gt;
                    &lt;asp:Label ID=&quot;lblPrefix&quot; runat=&quot;server&quot; /&gt;:&amp;nbsp;
                    &lt;asp:Label ID=&quot;lblSliderValue&quot; runat=&quot;server&quot; /&gt;&amp;nbsp;
                    &lt;asp:Label ID=&quot;lblSuffix&quot; runat=&quot;server&quot; /&gt;
                &lt;/td&gt;
                &lt;td style=&quot;text-align:right;width:40%;&quot;&gt;                
                    
                        &lt;asp:TextBox ID=&quot;txtSlider&quot; runat=&quot;server&quot; Text=&quot;50&quot; style=&quot;display:none;&quot; /&gt;
                        &lt;ajaxToolkit:SliderExtender ID=&quot;seSlider&quot; runat=&quot;server&quot; 
                            BehaviorID=&quot;seSlider&quot; 
                            TargetControlID=&quot;txtSlider&quot; 
                            BoundControlID=&quot;lblSliderValue&quot; 
                            Orientation=&quot;Horizontal&quot; 
                            EnableHandleAnimation=&quot;true&quot; 
                            Length=&quot;200&quot; 
                            Minimum=&quot;0&quot; 
                            Maximum=&quot;100&quot; 
                            Steps=&quot;1&quot; /&gt;
                    
                &lt;/td&gt;
            &lt;/tr&gt;
        &lt;/tbody&gt;
    &lt;/table&gt;

What is the problem?


&quot;The Controls collection cannot be modified because the control contains code blocks&quot;

I am just coming up to speed on WPF and would like to create a reusable WPF control.  

When I look at the options for creating projects in Visual Studio, I see &quot;WPF User Control Library&quot; and &quot;WPF Custom Control Library&quot;.  It&#39;s unclear to me what the difference is between them and my Google searches have not turned up any decent explanations.

I&#39;d like to understand the differences between them and ideally see some examples of when to use one over the other.

What is the difference between a User Control Library and a Custom Control Library?

I need to be able to get at the full URL of the page I am on from a user control.  Is it just a matter of concatenating a bunch of Request variables together?  If so which ones? Or is there a more simpiler way?

How do I get the full url of the page I am on in C#

I have created a custom WPF user control which is intended to be used by a third party. My control has a private member which is disposable, and I would like to ensure that its dispose method will always get called once the containing window/application is closed. However, UserControl is not disposable. 

I tried implementing the IDisposable interface and subscribing to the Unloaded event but neither get called when the host application closes. MSDN says that the Unloaded event may not be raised at all. And it might also be triggered more than once, that is when user changes theme. 

If at all possible, I don&#39;t want to rely on consumers of my control remembering to call a specific Dispose method.

     public partial class MyWpfControl : UserControl
     {
         SomeDisposableObject x;

         // where does this code go?
         void Somewhere() 
         {
             if (x != null)
             {
                 x.Dispose();
                 x = null;
             }

         }
     }

The only solution I have found so far is to subscribe to the Dispatcher&#39;s ShutdownStarted event. Is this a reasonable approach?

    this.Dispatcher.ShutdownStarted += Dispatcher_ShutdownStarted;

Disposing WPF User Controls

In my application i am constantly moving from one control to another. I have created no. of user controls, but during navigation my controls gets flicker. it takes 1 or 2 sec to update. I tried to set this

    SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
    or
    SetStyle(ControlStyles.UserPaint, true);
    SetStyle(ControlStyles.AllPaintingInWmPaint, true); 
    SetStyle(ControlStyles.DoubleBuffer, true);

but it didn&#39;t help... Each control has same background image with different controls.
So what is the solution for it..
&lt;br&gt;Thanks.
     

How to fix the flickering in User controls

I have a set of controls with attached commands and logic that are constantly reused in the same way.  I decided to create a user control that holds all the common controls and logic. 

However I also need the control to be able to hold content that can be named.  I tried the following:

&lt;!-- language: xaml --&gt;

    &lt;UserControl.ContentTemplate&gt;
        &lt;DataTemplate&gt;
            &lt;Button&gt;a reused button&lt;/Button&gt;
            &lt;ContentPresenter Content=&quot;{TemplateBinding Content}&quot;/&gt;
            &lt;Button&gt;a reused button&lt;/Button&gt;
        &lt;/DataTemplate&gt;
    &lt;/UserControl.ContentTemplate&gt;

However it seems any content placed inside the user control cannot be named.  For example if I use the control in the following way:

&lt;!-- language: xaml --&gt;

    &lt;lib:UserControl1&gt;
         &lt;Button Name=&quot;buttonName&quot;&gt;content&lt;/Button&gt;
    &lt;/lib:UserControl1&gt;

I receive the following error:

&gt; Cannot set Name attribute value &#39;buttonName&#39;
&gt; on element &#39;Button&#39;. &#39;Button&#39; is
&gt; under the scope of element
&gt; &#39;UserControl1&#39;, which already had a
&gt; name registered when it was defined in
&gt; another scope.

If I remove the buttonName, then it compiles, however I need to be able to name the content. How can I achieve this?

How to create a WPF UserControl with NAMED content

Call me crazy, but I&#39;m the type of guy that likes constructors with parameters (if needed), as opposed to a constructor with no parameters followed by setting properties. My thought process: if the properties are required to actually construct the object, they should go in the constructor. I get two advantages:

1. I know that when an object is constructed (without error/exception), my object is good.
2. It helps avoid forgetting to set a certain property.

This mindset is starting to hurt me in regards to form/usercontrol development. Imagine this `UserControl`:

    public partial class MyUserControl : UserControl
    {
      public MyUserControl(int parm1, string parm2)
      {
        // We&#39;ll do something with the parms, I promise
        InitializeComponent();
      }
    }

At designtime, if I drop this `UserControl` on a form, I get an `Exception`:

&gt; Failed to create component &#39;MyUserControl&#39; ...&lt;br&gt;
    System.MissingMethodException - No parameterless constructor defined for this object.

It seems like, to me, the only way around that was to add the default constructor (unless someone else knows a way).

    public partial class MyUserControl : UserControl
    {
      public MyUserControl()
      {
        InitializeComponent();
      }

      public MyUserControl(int parm1, string parm2)
      {
        // We&#39;ll do something with the parms, I promise
        InitializeComponent();
      }
    }

The whole point of not including the parameterless constructor was to avoid using it. And I can&#39;t even use the `DesignMode` property to do something like:

    public partial class MyUserControl : UserControl
    {
      public MyUserControl()
      {
        if (this.DesignMode)
        {
          InitializeComponent();
          return;
        }

        throw new Exception(&quot;Use constructor with parameters&quot;);
      }
    }

This doesn&#39;t work either:

    if (LicenseManager.UsageMode == LicenseUsageMode.Designtime)

Fine, moving along ...

I have my parameterless constructor, I can drop it on the form, and the form&#39;s `InitializeComponent` will look like this:

    private void InitializeComponent()
    {
      this.myControl1 = new MyControl();

      // blah, blah
    }

And trust me, because I did it (yes, ignoring the comments Visual Studio generated), I tried messing around and I passed parameters to `InitializeComponent` so that I could pass them to the constructor of `MyControl`.

Which leads me to this:

    public MyForm()
    {
      InitializeComponent(); // Constructed once with no parameters

      // Constructed a second time, what I really want
      this.myControl1 = new MyControl(anInt, aString);  
    }

For me to use a `UserControl` with parameters to the constructor, I have to add a second constructor that I don&#39;t need? And instantiate the control twice?

I feel like I must be doing something wrong. Thoughts? Opinions? Assurance (hopefully)?


&#39;UserControl&#39; constructor with parameters in C#

The following WPF UserControl called **DataTypeWholeNumber** which works.

Now I want to make a UserControl called **DataTypeDateTime** and **DataTypeEmail**, etc.

Many of the Dependency Properties will be shared by all these controls and therefore I want to put **their common methods into a BaseDataType** and have each of these UserControls inherit from this base type.

However, when I do that, I get the ***error: Partial Declaration may not have different base classes***.

So how can I implement inheritance with UserControls so shared functionality is all in the base class?


    using System.Windows;
    using System.Windows.Controls;
    
    namespace TestDependencyProperty827.DataTypes
    {
        public partial class DataTypeWholeNumber : BaseDataType
        {
            public DataTypeWholeNumber()
            {
                InitializeComponent();
                DataContext = this;
    
                //defaults
                TheWidth = 200;
            }
    
            public string TheLabel
            {
                get
                {
                    return (string)GetValue(TheLabelProperty);
                }
                set
                {
                    SetValue(TheLabelProperty, value);
                }
            }
    
            public static readonly DependencyProperty TheLabelProperty =
                DependencyProperty.Register(&quot;TheLabel&quot;, typeof(string), typeof(BaseDataType),
                new FrameworkPropertyMetadata());
    
    
            public string TheContent
            {
                get
                {
                    return (string)GetValue(TheContentProperty);
                }
                set
                {
                    SetValue(TheContentProperty, value);
                }
            }
    
            public static readonly DependencyProperty TheContentProperty =
                DependencyProperty.Register(&quot;TheContent&quot;, typeof(string), typeof(BaseDataType),
                new FrameworkPropertyMetadata());
    
    
            public int TheWidth
            {
                get
                {
                    return (int)GetValue(TheWidthProperty);
                }
                set
                {
                    SetValue(TheWidthProperty, value);
                }
            }
    
            public static readonly DependencyProperty TheWidthProperty =
                DependencyProperty.Register(&quot;TheWidth&quot;, typeof(int), typeof(DataTypeWholeNumber),
                new FrameworkPropertyMetadata());
                
    
    
        }
    }



How can a WPF UserControl inherit a WPF UserControl?

Has anyone found a useful solution to the DesignMode problem when developing controls?

The issue is that if you nest controls then DesignMode only works for the first level.  The second and lower levels DesignMode will always return FALSE.

The standard hack has been to look at the name of the process that is running and if it is &quot;DevEnv.EXE&quot; then it must be studio thus DesignMode is really TRUE.

The problem with that is looking for the ProcessName works its way around through the registry and other strange parts with the end result that the user might not have the required rights to see the process name.  In addition this strange route is very slow.  So we have had to pile additional hacks to use a singleton and if an error is thrown when asking for the process name then assume that DesignMode is FALSE.

A nice clean way to determine DesignMode is in order.  Acually getting Microsoft to fix it internally to the framework would be even better!

DesignMode with nested Controls

I have a custom usercontrol and I want to do something relatively simple.

When ever a numeric up down in that usercontrol&#39;s value changes, have the main form update a display window.

This is not a problem if the NUD was not in a usercontrol but I can&#39;t seem to figure out how to have the event handled by the mainform and not the usercontrol.


How do I make an Event in the Usercontrol and have it handled in the Main Form?

I have developed a User Control in Visual Studio (WinForms C#) and have a question.

I need the user of my User Control to be able to change certain string values and I would like them to be able to add the user control to their Form and click on it to bring up the Properties Pane where my User Control&#39;s custom properties will be displayed.

How can I have my own custom properties for my user control? For example:

My user control contains a TextBox, and I would like the user to be able to change the value of that TextBox via a property named &quot;Text&quot; or &quot;Value&quot; in the properties at Design-Time.

User Control - Custom Properties

I have some UserControls that I created in ProjectA.  I have ProjectB that has a windows form that I want to put the controls on.  Both of these projects are in a single solution.  There&#39;s a reference to ProjectA from ProjectB so it can &quot;see&quot; the UserControls.

However, the UserControls do not show up in the toolbox for me to drag to the windows form.

I&#39;ve tried rebuilding.  I&#39;ve also deleted the &#39;bin&#39; directory to force a rebuild-all.

How do I get VS2008 to populate the toolbox with my UserControls?

User Controls not showing up in the toolbox

I have a user control that I&#39;ve created, however when I go to add it to the XAML in the window, Intellisense doesn&#39;t pick it up, and I can&#39;t figure out how to add it to the window.


Add a user control to a wpf window

I have an existing library (not a Winforms application) that supplies some Winforms to a bona-fide Windows application.  Within this library, I would like to create a User Control to group some controls together.  To accomplish this, I **right-clicked, Add, User Control** and dragged some controls onto the new User Control.  

So far, so good.  The User Control even has the requisite User Control icon.  But dragging the new User Control from the Solution Explorer to a new blank Winform does not work (I get a circle with a line through it), and dragging it over to the Toolbox doesn&#39;t work either (even though I get a + sign when I drag it over the Toolbox).

Is there some sort of XML magic or something else I&#39;m missing to make this work?

---

**Note:** I had some problems with Visual Studio 2008 that I managed to fix by following the workarounds that can be found [here](http://connect.microsoft.com/VisualStudio/feedback/details/363321/choose-items-in-toolbox-causes-visual-studio-2008-sp1-to-crash).  I am now able to get User Controls I added to my existing project into the toolbox by simply rebuilding the project.

How do I add my new User Control to the Toolbox or a new Winform?

I am attempting to create a custom User Control that is usable in the Acumatica Framework. Documentation is very limited so I was hoping someone may have some experience/examples of how best to implement?

It appears possible by creating a `WebControl` derived from `PXWebControl` and creating a global *JS* function with a matching name.

Create custom User Control for Acumatica

I have a DataTable which has 5 columns:

* ID
* Name
* Account Number
* Branch 
* Amount

The DataTable contains 5 rows.

How can I show the sum of the Amount Column in a Label Control as &quot;Total Amount&quot;?

How to calculate the sum of the datatable column in asp.net?

I&#39;m trying to create a user control that has a `Grid` with two rows.
the first row for a title and the second one for a content that will be defined outside the user control such as a `Button` in our example.

Somehow I didn&#39;t get it to work.

UserControl1 xaml:

      &lt;Grid Background=&quot;LightBlue&quot;&gt;
        &lt;Grid.RowDefinitions&gt;
            &lt;RowDefinition Height=&quot;50&quot; /&gt;
            &lt;RowDefinition Height=&quot;*&quot; /&gt;
        &lt;/Grid.RowDefinitions&gt;
        &lt;TextBlock Text=&quot;Title&quot; FontSize=&quot;30&quot; Margin=&quot;10,0,0,0&quot;/&gt;
    &lt;/Grid&gt;

MainWindow xaml:

     &lt;Grid&gt;
        &lt;local:UserControl1&gt;
            &lt;Button&gt;Click me&lt;/Button&gt;
        &lt;/local:UserControl1&gt;
    &lt;/Grid&gt;

The picture below should explain what&#39;s my problem:
![enter image description here][1]


  [1]: http://i.stack.imgur.com/ZVZ1p.png

WPF - Hosting content inside a UserControl

how can i check if a user is logged in in user control with asp.net mvc 

usually on a view page i use this 

    &lt;% if (User.Identity.IsAuthenticated) {%&gt;
      //Do something
    &lt;% } %&gt;

but i can&#39;t get this done on a user control 

check if user is logged in in user control Asp.net MVC

I&#39;ve been reading some explanations about the difference between User and Custom Controls, for example this:
http://www.wpftutorial.net/CustomVsUserControl.html 

I want to create, for example, a simple composition of a datagrid with 2 comboboxes which are responsible to change the values from the datagrid&#39;s items. I want to create a specific control for this because I&#39;m going to use it a lot of times. I would like to implement the logic behind and then in the xaml invocation I only have to specify the itemsSource.

For this example should I create a User or Custom control? Since I will have properties and logic, should I have a viewmodel for this control?

EDIT: Do you know some articles with clear conceptual separation between these 2 options?

Custom vs User control

I have a class which implements UserControl. In .NET 2005, a Dispose method is automatically created in the MyClass.Designer.cs partial class file that looks like this:

      protected override void Dispose(bool disposing)
      {
         if (disposing &amp;&amp; (components != null))
         {
            components.Dispose();
         }
         base.Dispose(disposing);
      }


If I want to add my own Dispose functionality, where would I put it? Since this file is generated, I don&#39;t want to add code here and risk it getting blown away.


How do I add Dispose functionality to a C# UserControl?

I&#39;ve got a WPF application with these three types of things...

  - WindowMain
  - UserControlZack
  - WindowModal

UserControlZack1 sits on my WindowMain...


    &lt;Window x:Class=&quot;WindowMain&quot;
            xmlns=&quot;http://schemas.microsoft.com/winfx/2006/xaml/presentation&quot;
            xmlns:x=&quot;http://schemas.microsoft.com/winfx/2006/xaml&quot;
            xmlns:local=&quot;clr-namespace:ProjectName&quot;
            ...
            Name=&quot;WindowMain&quot;&gt;
        &lt;Grid&gt;
            ...
            &lt;local:UserControlZack x:Name=&quot;UserControlZack1&quot; ... /&gt;
            ...
        &lt;/Grid&gt;
    &lt;/Window&gt;

UserControlZack1 displays a WindowModal dailog box...

&lt;pre&gt;
Partial Public Class UserControlZack

   ...

    Private Sub SomeButton_Click(...)
        &#39;instantiate the dialog box and open modally...
        Dim box As WindowModal = New WindowModal()
        box.Owner = ?????
        box.ShowDialog()
        &#39;process data entered by user if dialog box is accepted...
        If (box.DialogResult.GetValueOrDefault = True) Then
            _SomeVar = box.SomeVar
            ...
        End If
    End Sub

End Class
&lt;/pre&gt;

How do I set box.Owner to the correct Window, my running instance of WindowMain?

I cannot use `box.Owner = Me.Owner`, because &quot;&#39;Owner&#39; is not a member of &#39;ProjectName.UserControlZack&#39;.&quot;

I cannot use `box.Owner = Me.Parent`, because that returns a Grid, not the Window.

I cannot use `box.Owner = WindowMain`, because &quot;&#39;WindowMain&#39; is a type and cannot be used as an expression.&quot;

WPF: How do I set the Owner Window of a Dialog shown by a UserControl?

I&#39;m trying to access a user control which is inside the control template of a content control. Specifically:

      &lt;ContentControl x:Name=&quot;MyList&quot; &gt;
            &lt;ContentControl.Template&gt;
                &lt;ControlTemplate x:Name=&quot;MyControlTemplate&quot;&gt;
                    &lt;Border RenderTransformOrigin=&quot;0,0&quot; x:Name=&quot;border&quot;&gt;
                        &lt;UserControls:MyControl x:Name=&quot;MyControlName&quot; Width=&quot;100&quot; ViewModel=&quot;{Binding}&quot; /&gt;

I can access this.MyList but it says this.MyControlName is not found. How do I access the MyControlName object from code-behind in this situation?

Thanks!


How do I access an element of a control template from within code-behind

From a custom control based on `TextBox`, I created a property named `Items`, in this way:

    public class NewTextBox : TextBox
    {
        public ItemCollection Items { get; set; }
    }

When using the custom control in XAML, I cannot bind the property because it raises exception &quot;A &#39;Binding&#39; can only be set on a DependencyProperty of a DependencyObject.&quot;.

How do I solve this exception?

A &#39;Binding&#39; can only be set on a DependencyProperty of a DependencyObject

I have an Outlook 2013 and 2016 VSTO Add-in project and am trying to add a WPF user control to a custom task pane as described [here][1].

The problem I have is when I add the User Control (WPF) it generates me a WPF control with a grid, but automatically throws an error of &quot;The type &#39;UserControl&#39; does not support direct content&quot;.

WPF generated:

    &lt;UserControl x:Class=&quot;TestNamespace.UserControl1&quot;
             xmlns=&quot;http://schemas.microsoft.com/winfx/2006/xaml/presentation&quot;
             xmlns:x=&quot;http://schemas.microsoft.com/winfx/2006/xaml&quot;
             xmlns:mc=&quot;http://schemas.openxmlformats.org/markup-compatibility/2006&quot; 
             xmlns:d=&quot;http://schemas.microsoft.com/expression/blend/2008&quot; 
             xmlns:local=&quot;clr-namespace:TestNamespace&quot;
             mc:Ignorable=&quot;d&quot; 
             d:DesignHeight=&quot;300&quot; d:DesignWidth=&quot;300&quot;&gt;
    &lt;Grid&gt;
            
    &lt;/Grid&gt;
    &lt;/UserControl&gt;

I know in the past I have had to add the WPF project type guid to the .proj file to get some things to work, but adding this made no difference (in fact it would not even load when in a certain order).

Original:

    &lt;ProjectTypeGuids&gt;{BAA0C2D2-18E2-41B9-852F-F413020CAA33};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}&lt;/ProjectTypeGuids&gt;
Crashes:

    &lt;ProjectTypeGuids&gt;{BAA0C2D2-18E2-41B9-852F-F413020CAA33};{60dc8134-eba5-43b8-bcc9-bb4bc16c2548};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}&lt;/ProjectTypeGuids&gt;

Doesn&#39;t crash, but doesn&#39;t fix the error:

    &lt;ProjectTypeGuids&gt;{60dc8134-eba5-43b8-bcc9-bb4bc16c2548};{BAA0C2D2-18E2-41B9-852F-F413020CAA33};{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}&lt;/ProjectTypeGuids&gt;

Can anyone point me in the right direction?

**UPDATE**

I tried creating a new class library project straight out of the box, added a WPF user control, then added the reference to System.Xaml and I have the same issue.

  [1]: https://msdn.microsoft.com/en-us/library/bb772076.aspx

The type &#39;UserControl&#39; does not support direct content

Is there any difference between drop down box and combo box [ HTML ]?  

Actually the point is, everytime i say something like: &quot;*there is some problem with the combo box*&quot;, my senior says: &quot;*that&#39;s not a combo box that is a drop down*&quot;,  :)

Is there any difference between drop down box and combo box?

When creating a UserControl in WPF, I find it convenient to give it some arbitrary Height and Width values so that I can view my changes in the Visual Studio designer. When I run the control, however, I want the Height and Width to be undefined, so that the control will expand to fill whatever container I place it in. How can I acheive this same functionality without having to remove the Height and Width values before building my control? (Or without using DockPanel in the parent container.)

The following code demonstrates the problem:

    &lt;Window x:Class=&quot;ExampleApplication3.Window1&quot;
        xmlns=&quot;http://schemas.microsoft.com/winfx/2006/xaml/presentation&quot;
        xmlns:x=&quot;http://schemas.microsoft.com/winfx/2006/xaml&quot;
        xmlns:loc=&quot;clr-namespace:ExampleApplication3&quot;
        Title=&quot;Example&quot; Height=&quot;600&quot; Width=&quot;600&quot;&gt;
        &lt;Grid Background=&quot;LightGray&quot;&gt;
            &lt;loc:UserControl1 /&gt;
        &lt;/Grid&gt;
    &lt;/Window&gt;

The following definition of `UserControl1` displays reasonably at design time but displays as a fixed size at run time:

    &lt;UserControl x:Class=&quot;ExampleApplication3.UserControl1&quot;
        xmlns=&quot;http://schemas.microsoft.com/winfx/2006/xaml/presentation&quot;
        xmlns:x=&quot;http://schemas.microsoft.com/winfx/2006/xaml&quot;
        Height=&quot;300&quot; Width=&quot;300&quot;&gt;
        &lt;Grid Background=&quot;LightCyan&quot; /&gt;
    &lt;/UserControl&gt;

The following definition of `UserControl1` displays as a dot at design time but expands to fill the parent `Window1` at run time:

    &lt;UserControl x:Class=&quot;ExampleApplication3.UserControl1&quot;
        xmlns=&quot;http://schemas.microsoft.com/winfx/2006/xaml/presentation&quot;
        xmlns:x=&quot;http://schemas.microsoft.com/winfx/2006/xaml&quot;&gt;
        &lt;Grid Background=&quot;LightCyan&quot; /&gt;
    &lt;/UserControl&gt;




WPF UserControl Design Time Size

Since there are no header sections for user controls in asp.net, user controls have no way of knowing about stylesheet files. So css classes in the user controls are not recognized by visual studio and produces warnings. How can I make a user control know that it will relate to a css class, so if it is warning me about a non-existing css class, it means that the class really do not exist?

Edit: Or should I go for a different design like exposing css classes as properties like &quot;HeaderStyle-CssClass&quot; of GridView?

How to make user controls know about css classes in ASP.NET

If I create a UserControl and add some objects to it, how can I grab the HTML it would render?

ex.

    UserControl myControl = new UserControl();
    myControl.Controls.Add(new TextBox());

    // ...something happens
    
    return strHTMLofControl;

I&#39;d like to just convert a newly built UserControl to a string of HTML.

All User Controls Solutions on Gang of Coders

Total of 28 User Controls Solutions

"The Controls collection cannot be modified because the control contains code blocks"