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ListBox.SelectedIndexCollection Class

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

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in system.windows.forms.dll)

public class SelectedIndexCollection : IList, ICollection, IEnumerable
public class SelectedIndexCollection implements IList, ICollection, 
	IEnumerable
public class SelectedIndexCollection implements IList, ICollection, 
	IEnumerable

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.

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.

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);
   }
}

    private void FindAllOfMyString(String searchString)
    {
        // Set the SelectionMode property of the ListBox to 
        // select multiple items.
        listBox1.set_SelectionMode(SelectionMode.MultiExtended);
        // Set our intial index variable to -1.
        int x = -1;

        // If the search string is empty exit.
        if (searchString.get_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.get_SelectedIndices().get_Count() > 0) {
                        if (x == listBox1.get_SelectedIndices().get_Item(0)) {
                            return;
                        }
                    }
                    // Select the item in the ListBox once it is found.
                    listBox1.SetSelected(x, true);
                }
            } while (x != -1);
        }
    } //FindAllOfMyString 
} //Form1

System.Object
  System.Windows.Forms.ListBox.SelectedIndexCollection
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0
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