Selection in Windows Forms ComboBox (SfComboBox)

18 Mar 20229 minutes to read

The Windows Forms ComboBox (SfComboBox) allows you to select single or multiple items in the drop-down list. The selection mode can be set by using the ComboBoxMode property.

Combo box has two different modes:

• SingleSelection: Selects single item.
• MultiSelection: Selects multiple items.

Single selection

Getting the selected index

Index of the selected item can be retrieved by using the SelectedIndex property.

Getting the selected value

Value of the selected item can be retrieved by using the SelectedValue property. It returns the property value bind to the ValueMember property. If the ValueMember is not initialized, it will return the value of the property bind to DisplayMember.

Getting the selected item of underlying data object

The selected item of the SfComboBox can be retrieved by using the SelectedItem property.

Events

SelectedIndexChanged event

The SelectedIndexChanged event is raised while selecting an item.

sfComboBox1.SelectedIndexChanged += new EventHandler(SfComboBox1_SelectedIndexChanged);
private void SfComboBox1_SelectedIndexChanged(object sender, EventArgs e)
{
}

sfComboBox1.SelectedValueChanged += new EventHandler(SfComboBox1_SelectedValueChanged);
private void SfComboBox1_SelectedValueChanged(object sender, EventArgs e)
{
}

SelectedValueChanged event

The SelectedValueChanged event is raised while selecting an item.

sfComboBox1.SelectedValueChanged += new EventHandler(SfComboBox1_SelectedValueChanged);
private void SfComboBox1_SelectedValueChanged(object sender, EventArgs e)
{
}

AddHandler sfComboBox1.SelectedValueChanged, AddressOf SfComboBox1_SelectedValueChanged
Private Sub SfComboBox1_SelectedValueChanged(ByVal sender As Object, ByVal e As EventArgs)
End Sub

Multi-selection

The SfComboBox allows you to select multiple values from the drop-down list. The WinForms multi-select combo box mode can be enabled by setting the ComboBoxMode property as MultiSelection.

sfComboBox1.ComboBoxMode = ComboBoxMode.MultiSelection;

sfComboBox1.ComboBoxMode = ComboBoxMode.MultiSelection

Select all

The SfComboBox support to choose all items in the drop-down list for multiselect combo box by setting the AllowSelectAll property to true.

sfComboBox1.AllowSelectAll = true;

sfComboBox1.AllowSelectAll = True

Changing the delimiter character to separate selected items

The SfComboBox supports various delimiter characters to separate multiple selected items in the multi selected combo box. The delimiter character can be set by using the DelimiterChar property. The default delimiter character is “,”.

sfComboBox1.DelimiterChar = "-";

sfComboBox1.DelimiterChar = "-"

Hiding the buttons in the drop down

Buttons in the drop-down list can be hide by setting the DropDownControl.ShowButtons property to false.

sfComboBox1.DropDownControl.ShowButtons = false;

sfComboBox1.DropDownControl.ShowButtons = False

Accessing the checked items

The checked items can be retrieved by using the CheckedItems property. The items can also be added programmatically by using the CheckedItems property.

Tooltip

Multi-select combo box supports to show the whole text in the editor portion by using the tooltip when hovering the mouse on the editor portion of the control. Tooltip can be enabled by setting the ShowToolTip property to true.

NOTE

The SfToolTip control is used for the tooltip support.

sfComboBox1.ShowToolTip = true;

sfComboBox1.ShowToolTip = True

Tooltip options

Setting tooltip delay

Tooltip support you to set delay when showing the tooltip values by using the ToolTipOption property.

The following properties can be used to set the tooltip delay time:

• InitialDelay
• AutoPopDelay.

InitialDelay

The InitialDelay property enables you to shorten or lengthen the time that the tooltip waits before displaying the tooltip values. The default value is 500 milliseconds.

sfComboBox1.ToolTipOption.InitialDelay = 3000;

sfComboBox1.ToolTipOption.InitialDelay = 3000

AutoPopDelay

The AutoPopDelay property enables you to shorten or lengthen the time duration that the tooltip is displayed when the mouse pointer is on a control. The default value is 5000 milliseconds.

sfComboBox1.ToolTipOption.AutoPopDelay = 2000;

sfComboBox1.ToolTipOption.AutoPopDelay = 2000

ToolTip shadow

Shadow of the tooltip can be enabled or disabled by setting the ShadowVisible property. Default value is true .

sfComboBox1.ToolTipOption.ShadowVisible = false;

sfComboBox1.ToolTipOption.ShadowVisible = False

Styling

Appearance of the tooltip can be customized by using the ToolTipStyle property.

sfComboBox1.Style.ToolTipStyle.BackColor = Color.Green;
sfComboBox1.Style.ToolTipStyle.ForeColor = Color.White;
sfComboBox1.Style.ToolTipStyle.BorderColor = Color.Red;
sfComboBox1.Style.ToolTipStyle.BorderThickness = 5;

sfComboBox1.Style.ToolTipStyle.BackColor = Color.Green
sfComboBox1.Style.ToolTipStyle.ForeColor = Color.White
sfComboBox1.Style.ToolTipStyle.BorderColor = Color.Red
sfComboBox1.Style.ToolTipStyle.BorderThickness = 5

Conditional styling

Appearance of the tooltip can be customized before showing the tooltip based on the control in which it is configured by using the ToolTipOpening event.

sfComboBox1.ToolTipOpening += new EventHandler<ComboBoxToolTipOpeningEventArgs>(SfComboBox1_ToolTipOpening);
private void SfComboBox1_ToolTipOpening(object sender, ComboBoxToolTipOpeningEventArgs e)
{
  if (e.DisplayText.Contains("California"))
    {
       sfComboBox1.Style.ToolTipStyle.ForeColor = Color.Red;
    }
}

AddHandler sfComboBox1.ToolTipOpening, AddressOf SfComboBox1_ToolTipOpening
Private Sub SfComboBox1_ToolTipOpening(ByVal sender As Object, ByVal e As ComboBoxToolTipOpeningEventArgs)
  If e.DisplayText.Contains("California") Then
	   sfComboBox1.Style.ToolTipStyle.ForeColor = Color.Red
  End If
End Sub

Canceling tooltip opening

The ToolTipOpening event can be used to cancel the tooltip opening by setting the e.Cancel to true.

sfComboBox1.ToolTipOpening += new EventHandler<ComboBoxToolTipOpeningEventArgs>(SfComboBox1_ToolTipOpening);
private void SfComboBox1_ToolTipOpening(object sender, ComboBoxToolTipOpeningEventArgs e)
{
   e.Cancel = true;
}

AddHandler sfComboBox1.ToolTipOpening, AddressOf SfComboBox1_ToolTipOpening
Private Sub SfComboBox1_ToolTipOpening(ByVal sender As Object, ByVal e As ComboBoxToolTipOpeningEventArgs)
   e.Cancel = True
End Sub

Clear selection

The SfComboBox allows to show or hide the clear button by using the ShowClearButton property. When pressing the clear button it will clear the selected items and editor portion.

NOTE

This clear button will be visible only when the selection or editing takes place inside the SfComboBox.

sfComboBox1.ShowClearButton = true;

Clear button appearance

Appearance of the clear button can be customized by setting the ClearButtonStyle property.

sfComboBox1.ShowClearButton = true;
      
sfComboBox1.Style.ClearButtonStyle.BackColor = Color.Yellow;
sfComboBox1.Style.ClearButtonStyle.ForeColor = Color.Red;
sfComboBox1.Style.ClearButtonStyle.HoverBackColor = Color.OrangeRed;
sfComboBox1.Style.ClearButtonStyle.HoverForeColor = Color.Yellow;