CheckedListBox.CheckedItemCollection Class

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Encapsulates the collection of checked items, including items in an indeterminate state, in a CheckedListBox control.

public: ref class CheckedListBox::CheckedItemCollection : System::Collections::IList

public class CheckedListBox.CheckedItemCollection : System.Collections.IList

type CheckedListBox.CheckedItemCollection = class
    interface IList
    interface ICollection
    interface IEnumerable

Public Class CheckedListBox.CheckedItemCollection
Implements IList

Inheritance

Object

CheckedListBox.CheckedItemCollection

Implements

ICollection IEnumerable IList

Examples

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 ) ), "." ) );
   }
}

private 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.
    foreach(int indexChecked in checkedListBox1.CheckedIndices) {
        // The indexChecked variable contains the index of the item.
        MessageBox.Show("Index#: " + indexChecked.ToString() + ", is checked. Checked state is:" +
                        checkedListBox1.GetItemCheckState(indexChecked).ToString() + ".");
    }

    // Next show the object title and check state for each item selected.
    foreach(object itemChecked in checkedListBox1.CheckedItems) {

        // Use the IndexOf method to get the index of an item.
        MessageBox.Show("Item with title: \"" + itemChecked.ToString() +
                        "\", is checked. Checked state is: " +
                        checkedListBox1.GetItemCheckState(checkedListBox1.Items.IndexOf(itemChecked)).ToString() + ".");
    }
}

Private Sub WhatIsChecked_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles WhatIsChecked.Click
    ' Display in a message box all the items that are checked.
    Dim indexChecked As Integer
    Dim itemChecked As Object
    Const quote As String = """"

    ' First show the index and check state of all selected items.
    For Each indexChecked In CheckedListBox1.CheckedIndices
        ' The indexChecked variable contains the index of the item.
        MessageBox.Show("Index#: " + indexChecked.ToString() + ", is checked. Checked state is:" + _
                        CheckedListBox1.GetItemCheckState(indexChecked).ToString() + ".")
    Next

    ' Next show the object title and check state for each item selected.
    For Each itemChecked In CheckedListBox1.CheckedItems

        ' Use the IndexOf method to get the index of an item.
        MessageBox.Show("Item with title: " + quote + itemChecked.ToString() + quote + _
                        ", is checked. Checked state is: " + _
                        CheckedListBox1.GetItemCheckState(CheckedListBox1.Items.IndexOf(itemChecked)).ToString() + ".")
    Next

End Sub

Remarks

The checked items collection is a subset of all items in the CheckedListBox control; it contains only those items that are 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	Unchecked
1	object 2	Checked
2	object 3	Unchecked
3	object 4	Indeterminate
4	object 5	Checked

Based on the previous example, the following table shows the indexed collection of the checked items.

Index	Item
0	object 2
1	object 4
2	object 5

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 object 4. A call to IndexOf with a parameter of object 4 returns a value of 1.

Properties

Count	Gets the number of items in the collection.
IsReadOnly	Gets a value indicating if the collection is read-only.
Item[Int32]	Gets an object in the checked items collection.

Methods

Contains(Object)	Determines whether the specified item is located in 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 that can be used to iterate through the CheckedItems collection.
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IndexOf(Object)	Returns an index into the collection of checked items.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
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.Insert(Int32, Object)	For a description of this member, see Insert(Int32, Object).
IList.IsFixedSize	For a description of this member, see IsFixedSize.
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