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ListBox.GetSelected Method

Returns a value indicating whether the specified item is selected.

[Visual Basic]
Public Function GetSelected( _
   ByVal index As Integer _
) As Boolean
[C#]
public bool GetSelected(
 int index
);
[C++]
public: bool GetSelected(
 int index
);
[JScript]
public function GetSelected(
   index : int
) : Boolean;

Parameters

index
The zero-based index of the item that determines whether it is selected.

Return Value

true if the specified item is currently selected in the ListBox; otherwise, false.

Exceptions

Exception Type Condition
ArgumentOutOfRangeException The index parameter is less than zero or greater than or equal to the value of the Count property of the ListBox.ObjectCollection class.

Remarks

You can used this method to quickly determine whether a specified item is selected. This method is useful when a specific operation needs to be performed when a specific item in a multiple-selection ListBox is selected.

Example

[Visual Basic, C#, C++] The following example demonstrates how to use the GetSelected method to determine which items in a ListBox are selected in order to select the items that are not selected and deselect the items that are selected. The example also demonstrates using the SelectionMode property to enable a ListBox to have more than one selected item and uses the Sorted property to demonstrate how to sort items in a ListBox automatically. This example assumes that a ListBox, named listBox1, has been added to a form and that the InitializeMyListBox method defined in the example is called from the Load event of the form.

[Visual Basic] 
Private Sub InitializeMyListBox()
   ' Add items to the ListBox.
   listBox1.Items.Add("A")
   listBox1.Items.Add("C")
   listBox1.Items.Add("E")
   listBox1.Items.Add("F")
   listBox1.Items.Add("G")
   listBox1.Items.Add("D")
   listBox1.Items.Add("B")

   ' Sort all items added previously.
   listBox1.Sorted = True

   ' Set the SelectionMode to select multiple items.
   listBox1.SelectionMode = SelectionMode.MultiExtended

   ' Select three initial items from the list.
   listBox1.SetSelected(0, True)
   listBox1.SetSelected(2, True)
   listBox1.SetSelected(4, True)

   ' Force the ListBox to scroll back to the top of the list.
   listBox1.TopIndex = 0
End Sub

Private Sub InvertMySelection()

   Dim x As Integer
   ' Loop through all items the ListBox.
   For x = 0 To listBox1.Items.Count - 1

      ' Determine if the item is selected.
      If listBox1.GetSelected(x) = True Then
         ' Deselect all items that are selected.
         listBox1.SetSelected(x, False)
      Else
         ' Select all items that are not selected.
         listBox1.SetSelected(x, True)
      End If
   Next x
   ' Force the ListBox to scroll back to the top of the list.
   listBox1.TopIndex = 0
End Sub

[C#] 
private void InitializeMyListBox()
{
   // Add items to the ListBox.
   listBox1.Items.Add("A");
   listBox1.Items.Add("C");
   listBox1.Items.Add("E");
   listBox1.Items.Add("F");
   listBox1.Items.Add("G");
   listBox1.Items.Add("D");
   listBox1.Items.Add("B");

   // Sort all items added previously.
   listBox1.Sorted = true;

   // Set the SelectionMode to select multiple items.
   listBox1.SelectionMode = SelectionMode.MultiExtended;

   // Select three initial items from the list.
   listBox1.SetSelected(0,true);
   listBox1.SetSelected(2,true);
   listBox1.SetSelected(4,true);

   // Force the ListBox to scroll back to the top of the list.
   listBox1.TopIndex=0;
}

private void InvertMySelection()
{
   // Loop through all items the ListBox.
   for (int x = 0; x < listBox1.Items.Count; x++)
   {
      // Determine if the item is selected.
      if(listBox1.GetSelected(x) == true)
         // Deselect all items that are selected.
         listBox1.SetSelected(x,false);      
      else
         // Select all items that are not selected.
         listBox1.SetSelected(x,true);
   }
   // Force the ListBox to scroll back to the top of the list.
   listBox1.TopIndex=0;
}

[C++] 
private:
   void InitializeMyListBox()
   {
      // Add items to the ListBox.
      listBox1->Items->Add(S"A");
      listBox1->Items->Add(S"C");
      listBox1->Items->Add(S"E");
      listBox1->Items->Add(S"F");
      listBox1->Items->Add(S"G");
      listBox1->Items->Add(S"D");
      listBox1->Items->Add(S"B");

      // Sort all items added previously.
      listBox1->Sorted = true;

      // Set the SelectionMode to select multiple items.
      listBox1->SelectionMode = SelectionMode::MultiExtended;

      // Select three initial items from the list.
      listBox1->SetSelected(0,true);
      listBox1->SetSelected(2,true);
      listBox1->SetSelected(4,true);

      // Force the ListBox to scroll back to the top of the list.
      listBox1->TopIndex=0;
   }

   void InvertMySelection()
   {
      // Loop through all items the ListBox.
      for (int x = 0; x < listBox1->Items->Count; x++)
      {
         // Select all items that are not selected,
         // deselect all items that are selected.
         listBox1->SetSelected(x, !listBox1->GetSelected(x));      
      }
      // Force the ListBox to scroll back to the top of the list.
      listBox1->TopIndex=0;
   }

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

ListBox Class | ListBox Members | System.Windows.Forms Namespace

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