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• Using Controls (15)

• Why is my ComboBox slow to load when data binding?

  ComboBox loading performance issues are generally related to loading the data multiple times. The two most common scenarios for this are setting the DisplayMember after setting the DataSource or binding the ComboBox prior to filling the DataSource. Setting...

• How can I get the ComboBox to display multiple data source properties?

  ComboBox binding does not directly support data source property concatenation however you can use the ComboBox Format event to concatenate multiple data source properties. Sample: Concatenating data source properties using the Format event (VS 2005) ...

• How can I add a "null" or "DBNull" entry to my bound ComboBox?

  When data bound, the Windows Forms ComboBox does not provide a general way to add a "null" or "not selected" value to its items list. The only generally supported way to do this is to add a "null" item to your data source...

• How do I setup a ComboBox to bind to a Lookup table?

  A common use of a ComboBox in a data bound application is as a lookup based UI control. From a database perspective, a Lookup control is used to provide the "lookup" values for a foreign key. For example, assume you have a customer table with...

• What are the DisplayMember and ValueMember?

  You can fill a ComboBox with non-string items such as business objects. By default, the ComboBox will call ToString() on each of the items to generate the display text (visible text). Rather than rely on ToString(), you can have the ComboBox use one of...

• How do I set the SelectedItem property in a databound ComboBox?

  Use the FindStringExact method. For example, to set the ComboBox's ValueMember property to "OrderID", then you could call comboBox1.SelectedIndex = comboBox1.FindStringExact( stringOrderID ); where stringOrderID is the orderID of the row...

• How do I add a ComboBox button to a toolbar?

  Michael Gold discusses this problem in his article How to create a "ComboBox button" in a toolbar in .NET on C# Corner . Contributed from George Shepherd's Windows Forms FAQ

• How do I create an owner-drawn ComboBox?

  You can subclass ComboBox. In your derived class, make sure you set DrawMode = System.Windows.Forms.DrawMode.OwnerDrawFixed; DropDownStyle = ComboBoxStyle.DropDownList; You also need to handle the DrawItem event to actually implement the drawing. Check...

• How do I programmatically prevent the ComboBox drop-down list from dropping down?

  You can prevent the ComboBox dropping by overriding its WndProc method and ignoring the WM_LBUTTONDOWN and WM_LBUTTONDBLCLK. [C#] using System.Windows.Forms; public class CustomComboBox : ComboBox { protected override void WndProc( ref Message m ) { if...

• How do I set the width of a ComboBox to fit the entries in its list?

  You can iterate through the list to find the longest text extent using MeasureString, and then use this as the ComboBox width adding a fudge factor for the drop-down button. using ( Graphics g = comboBox1.CreateGraphics() ) { float maxWidth = 0f; foreach...

• How do I adjust the height of the of a ComboBox drop-down list?

  You can control the height by changing the value of the MaxDropDownItems property of the the ComboBox, which is the maximum number of entries that will be displayed in the drop-down list. Contributed from George Shepherd's Windows Forms FAQ

• How do I disable editing in the TextBox portion of a ComboBox, restricting the user to selecting items in the drop-down list?

  Set the ComboBox's DropDownStyle property to DropDownList. Contributed from George Shepherd's Windows Forms FAQ

• How do I programmatically create a new list for a ComboBox drop-down list?

  Here are some snippets. (Courtesy of) [C#] DataTable list = new DataTable(); list.Columns.Add(new DataColumn("Display", typeof(string))); list.Columns.Add(new DataColumn("Id", typeof(int))); list.Rows.Add(list.NewRow()); list.Rows...

• How do I bind the values of an enum to a ComboBox?

  The enum values can be bound to a combobox as follows: MyValues is the enum type [C#] // Setup the binding as follows: comboBox1.DataSource = Enum.GetValues(typeof MyValues); // SelectedValueChanged event for the ComboBox. private void ComboBox1ValueChanged...

• How do I fill a ComboBox with the available fonts?

  Try comboBox1.Items.AddRange( FontFamily.Families ); Contributed from George Shepherd's Windows Forms FAQ