CheckedListBox::CheckedIndexCollection Class
Encapsulates the collection of indexes of checked items (including items in an indeterminate state) in a CheckedListBox.
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
The CheckedListBox::CheckedIndexCollection type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | Count | Gets the number of checked items. |
![]() | IsReadOnly | Gets a value indicating whether the collection is read-only. |
![]() | Item | Gets the index of a checked item in the CheckedListBox control. |
| Name | Description | |
|---|---|---|
![]() | Contains | Determines whether the specified index is located in the collection. |
![]() | CopyTo | 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.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetEnumerator | Returns an enumerator that can be used to iterate through the CheckedIndices collection. |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | IndexOf | Returns an index into the collection of checked indexes. |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
| Name | Description | |
|---|---|---|
![]() | AsParallel | Enables parallelization of a query. (Defined by ParallelEnumerable.) |
![]() | AsQueryable | Converts an IEnumerable to an IQueryable. (Defined by Queryable.) |
![]() | Cast<TResult> | Casts the elements of an IEnumerable to the specified type. (Defined by Enumerable.) |
![]() | OfType<TResult> | Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.) |
| Name | Description | |
|---|---|---|
![]() ![]() | ICollection::IsSynchronized | Infrastructure. Gets a value indicating whether access to the CheckedListBox::CheckedIndexCollection is synchronized (thread safe). |
![]() ![]() | ICollection::SyncRoot | Infrastructure. Gets an object that can be used to synchronize access to the collection of controls. For a description of this member, see ICollection::SyncRoot. |
![]() ![]() | IList::Add | Infrastructure. Adds an item to the CheckedListBox::CheckedIndexCollection. For a description of this member, see IList::Add. |
![]() ![]() | IList::Clear | Infrastructure. Removes all items from the CheckedListBox::CheckedIndexCollection. For a description of this member, see IList::Clear. |
![]() ![]() | IList::Contains | Infrastructure. Determines whether the specified index is located within the CheckedListBox::CheckedIndexCollection. For a description of this member, see IList::Contains. |
![]() ![]() | IList::IndexOf | Infrastructure. For a description of this member, see IList::IndexOf. |
![]() ![]() | IList::Insert | Infrastructure. For a description of this member, see IList::Insert. |
![]() ![]() | IList::IsFixedSize | Infrastructure. For a description of this member, see IList::IsFixedSize. |
![]() ![]() | IList::Item | Infrastructure. For a description of this member, see IList::Item. |
![]() ![]() | IList::Remove | Infrastructure. For a description of this member, see IList::Remove. |
![]() ![]() | IList::RemoveAt | Infrastructure. or a description of this member, see IList::RemoveAt. |
The checked indexes collection is a subset of the indexes into the collection of all items in the CheckedListBox control. These indexes specify items in a checked or indeterminate state.
The following table is an example of the indexed collection of items in the control (all items contained in the control).
Index | Item | Check State |
|---|---|---|
0 | object 1 | |
1 | object 2 | |
2 | object 3 | |
3 | object 4 | |
4 | object 5 |
Based on the previous example, the following table shows the indexed collection of indexes of checked items.
Index | Index of Item |
|---|---|
0 | 1 |
1 | 3 |
2 | 4 |
The CheckedListBox class has two members that allow you to access the stored indexes, the Item property and the IndexOf method.
Based on the previous example, a call to the Item property with a parameter value of 1 returns a value of 3. A call to IndexOf with a parameter of 3 returns a value of 1.
The following example enumerates the checked items in the CheckedListBox::CheckedIndexCollection to see what check state an item is in. The example demonstrates using the GetItemCheckState method to set the check state of an item. The example also demonstrates using the CheckedIndices property to get the CheckedListBox::CheckedIndexCollection, and the CheckedItems property to get the CheckedListBox::CheckedItemCollection.
The first loop uses the GetItemCheckState method to get the CheckState of each checked item, given the index of the item. The second loop also uses GetItemCheckState, but uses the ListBox::ObjectCollection::IndexOf method to retrieve the index for the item.
void WhatIsChecked_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ ) { // Display in a message box all the items that are checked. // First show the index and check state of all selected items. IEnumerator^ myEnum1 = checkedListBox1->CheckedIndices->GetEnumerator(); while ( myEnum1->MoveNext() ) { Int32 indexChecked = *safe_cast<Int32^>(myEnum1->Current); // The indexChecked variable contains the index of the item. MessageBox::Show( String::Concat( "Index#: ", indexChecked, ", is checked. Checked state is: ", checkedListBox1->GetItemCheckState( indexChecked ), "." ) ); } // Next show the Object* title and check state for each item selected. IEnumerator^ myEnum2 = checkedListBox1->CheckedItems->GetEnumerator(); while ( myEnum2->MoveNext() ) { Object^ itemChecked = safe_cast<Object^>(myEnum2->Current); // Use the IndexOf method to get the index of an item. MessageBox::Show( String::Concat( "Item with title: \"", itemChecked, "\", is checked. Checked state is: ", checkedListBox1->GetItemCheckState( checkedListBox1->Items->IndexOf( itemChecked ) ), "." ) ); } }
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

