ListBox.SelectedIndexCollection Class

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

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

public: ref class ListBox::SelectedIndexCollection : System::Collections::IList

public class ListBox.SelectedIndexCollection : System.Collections.IList

type ListBox.SelectedIndexCollection = class
    interface IList
    interface ICollection
    interface IEnumerable

Public Class ListBox.SelectedIndexCollection
Implements IList

Inheritance

Object

ListBox.SelectedIndexCollection

Implements

ICollection IEnumerable IList

Examples

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.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 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

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.

Constructors

ListBox.SelectedIndexCollection(ListBox)

Initializes a new instance of the ListBox.SelectedIndexCollection class.

Properties

Count	Gets the number of items in the collection.
IsReadOnly	Gets a value indicating whether the collection is read-only.
Item[Int32]	Gets the index value at the specified index within this collection.

Methods

Add(Int32)	Adds the ListBox at the specified index location.
Clear()	Removes all controls from the collection.
Contains(Int32)	Determines whether the specified index is located within the collection.
CopyTo(Array, Int32)	Copies the entire collection into an existing array at a specified location within the array.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
GetEnumerator()	Returns an enumerator to use to iterate through the selected indexes collection.
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IndexOf(Int32)	Returns the index within the ListBox.SelectedIndexCollection of the specified index from the ListBox.ObjectCollection of the ListBox.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Remove(Int32)	Removes the specified control from the collection.
ToString()	Returns a string that represents the current object. (Inherited from Object)

Explicit Interface Implementations

ICollection.IsSynchronized	For a description of this member, see IsSynchronized.
ICollection.SyncRoot	For a description of this member, see SyncRoot.
IList.Add(Object)	For a description of this member, see Add(Object).
IList.Clear()	For a description of this member, see Clear().
IList.Contains(Object)	For a description of this member, see Contains(Object).
IList.IndexOf(Object)	For a description of this member, see IndexOf(Object).
IList.Insert(Int32, Object)	For a description of this member, see Insert(Int32, Object).
IList.IsFixedSize	For a description of this member, see IsFixedSize.
IList.Item[Int32]	For a description of this member, see Item[Int32].
IList.Remove(Object)	For a description of this member, see Remove(Object).
IList.RemoveAt(Int32)	For a description of this member, see RemoveAt(Int32).

Extension Methods