Linq Query keeps throwing "Unable to create a constant value of type System.Object....", Why?

The following is the code sample:

private void loadCustomer(int custIdToQuery) 
    {
        var dbContext = new SampleDB();
        try
        {
            var customerContext = from t in dbContext.tblCustomers		// keeps throwing:
                                   where t.CustID.Equals(custIdToQuery)	// Unable to create a constant value of type 'System.Object'. 
                                   select new							// Only primitive types ('such as Int32, String, and Guid') 
                                   {									// are supported in this context.
                                       branchId = t.CustomerBranchID,	//
                                       branchName = t.BranchName		//
                                   };									//

            if (customerContext.ToList().Count() < 1) //Already Tried customerContext.Any()
            {
                lstbCustomers.DataSource = customerContext;
                lstbCustomers.DisplayMember = "branchName";
                lstbCustomers.ValueMember = "branchId";
            }
            else
            {
                lstbCustomers.Items.Add("There are no branches defined for the selected customer.");
                lstbCustomers.Refresh();
            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
        finally
        {
            dbContext.Dispose();
        }
    }

i am unable to understand what am i doing wrong. I keep getting "Unable to create a constant value of type 'System.Object'. Only primitive types ('such as Int32, String, and Guid') are supported in this context."

Use == instead of Equals:

where t.CustID == custIdToQuery

If the types are incorrect you may find that this doesn't compile.

I had the same issue with a nullable int. Using == instead works nicely, but if you want to use .Equals, you can compare it to the value of the nullable variable, so

where t.CustID.Value.Equals(custIdToQuery)

I had the same issue when I was trying to do .Equals with a nullable decimal. Using == instead works nicely. I guess this is because it's not trying to match the exact "type" of decimal? to decimal.

I was faced the same issue and i was comparing Collection Object "User" with integer data type "userid" (x.User.Equals(userid))

from user in myshop.UserPermissions.Where(x => x.IsDeleted == false && x.User.Equals(userid))

and correct Query is x.UserId.Equals(userid)

from user in myshop.UserPermissions.Where(x => x.IsDeleted == false && x.UserId.Equals(userid))

In my case, I changed the direct call of (sender as Button).Text to indirect call using a temp var, has worked. working code:

private void onTopAccBtnClick(object sender, EventArgs e)
    {
        var name = (sender as Button).Text;
        accountBindingSource.Position =
                    accountBindingSource.IndexOf(_dataService.Db.Accounts.First(ac => ac.AccountName == name));
        accountBindingSource_CurrentChanged(sender, e);
    }

buggy code:

private void onTopAccBtnClick(object sender, EventArgs e)
    {
        accountBindingSource.Position =
                    accountBindingSource.IndexOf(_dataService.Db.Accounts.First(ac => ac.AccountName == (sender as Button).Text));
        accountBindingSource_CurrentChanged(sender, e);
    }