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ListBox.SelectedIndexCollection Class

Represents the collection containing the indexes to the selected items in a ListBox.

For a list of all members of this type, see ListBox.SelectedIndexCollection Members.

System.Object
   System.Windows.Forms.ListBox.SelectedIndexCollection

[Visual Basic]
Public Class ListBox.SelectedIndexCollection
   Implements IList, ICollection, IEnumerable
[C#]
public class ListBox.SelectedIndexCollection : IList, ICollection,
   IEnumerable
[C++]
public __gc class ListBox.SelectedIndexCollection : public IList,
   ICollection, IEnumerable
[JScript]
public class ListBox.SelectedIndexCollection implements IList,
   ICollection, IEnumerable

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Remarks

The ListBox.SelectedIndexCollection class stores the indexes to the selected items in the ListBox. The indexes stored in the ListBox.SelectedIndexCollection are index positions within the ListBox.ObjectCollection class. The ListBox.ObjectCollection class stores all items displayed in the ListBox.

The following table is an example of how the ListBox.ObjectCollection stores the items of the ListBox as well as their selection states within an example ListBox.

Index Item Selection State Within the ListBox
0 object1 Unselected
1 object2 Selected
2 object3 Unselected
3 object4 Selected
4 object5 Selected

Based on the ListBox.ObjectCollection example in the previous table, the following table demonstrates how the ListBox.SelectedIndexCollection would appear.

Index Index of Selected Item in ObjectCollection
0 1
1 3
2 4

You can use the properties and methods of this class to perform a variety of tasks with the collection. The Contains method enables you to determine whether an index position from the ListBox.ObjectCollection class is a member of the selected indexes stored in the ListBox.SelectedIndexCollection. Once you know that the item is located within the collection, you can use the IndexOf method to determine where a specific index position within the ListBox.ObjectCollection for the ListBox is stored.

Example

[Visual Basic, C#, C++] The following example demonstrates how to use the FindString method to search for all instances of the search text in the items of the ListBox. The example uses the version of the FindString method that enables you to specify a starting search index from which to do a continual search of all items in the ListBox. The example also demonstrates how to determine when the FindString method begins searching from the top of the list after it reaches the bottom of the list of items to prevent a recursive search. Once items are found in the ListBox, they are selected using the SetSelected method.

[Visual Basic] 
Private Sub FindAllOfMyString(ByVal searchString As String)
   ' Set the SelectionMode property of the ListBox to select multiple items.
   listBox1.SelectionMode = SelectionMode.MultiExtended

   ' Set our intial index variable to -1.
   Dim x As Integer = -1
   ' If the search string is empty exit.
   If searchString.Length <> 0 Then
      ' Loop through and find each item that matches the search string.
      Do
         ' Retrieve the item based on the previous index found. Starts with -1 which searches start.
         x = listBox1.FindString(searchString, x)
         ' If no item is found that matches exit.
         If x <> -1 Then
            ' Since the FindString loops infinitely, determine if we found first item again and exit.
            If ListBox1.SelectedIndices.Count > 0 Then
               If x = ListBox1.SelectedIndices(0) Then
                  Return
               End If
            End If
            ' Select the item in the ListBox once it is found.
            ListBox1.SetSelected(x, True)
         End If
      Loop While x <> -1
   End If
End Sub

[C#] 
private void FindAllOfMyString(string searchString)
{
   // Set the SelectionMode property of the ListBox to select multiple items.
   listBox1.SelectionMode = SelectionMode.MultiExtended;
   
   // Set our intial index variable to -1.
   int x =-1;
   // If the search string is empty exit.
   if (searchString.Length != 0)
   {
      // Loop through and find each item that matches the search string.
      do
      {
         // Retrieve the item based on the previous index found. Starts with -1 which searches start.
         x = listBox1.FindString(searchString, x);
         // If no item is found that matches exit.
         if (x != -1)
         {
            // Since the FindString loops infinitely, determine if we found first item again and exit.
            if (listBox1.SelectedIndices.Count > 0)
            {
               if(x == listBox1.SelectedIndices[0])
                  return;
            }
            // Select the item in the ListBox once it is found.
            listBox1.SetSelected(x,true);
         }
   
      }while(x != -1);
   }
}

[C++] 
private:
    void FindAllOfMyString(String* searchString)
    {
        // Set the SelectionMode property of the ListBox to select multiple items.
        listBox1->SelectionMode = SelectionMode::MultiExtended;

        // Set our intial index variable to -1.
        int x =-1;
        // If the search string is empty exit.
        if (searchString->Length != 0)
        {
            // Loop through and find each item that matches the search string.
            do
            {
                // Retrieve the item based on the previous index found. Starts with -1 which searches start.
                x = listBox1->FindString(searchString, x);
                // If no item is found that matches exit.
                if (x != -1)
                {
                    // Since the FindString loops infinitely, determine if we found first item again and exit.
                    if (listBox1->SelectedIndices->Count > 0)
                    {
                        if(x == listBox1->SelectedIndices->Item[0])
                            return;
                    }
                    // Select the item in the ListBox once it is found.
                    listBox1->SetSelected(x,true);
                }

            }while(x != -1);
        }
    }

[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

Namespace: System.Windows.Forms

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

Assembly: System.Windows.Forms (in System.Windows.Forms.dll)

See Also

ListBox.SelectedIndexCollection Members | System.Windows.Forms Namespace

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