ListBox.ObjectCollection.Add(Object) ListBox.ObjectCollection.Add(Object) ListBox.ObjectCollection.Add(Object) ListBox.ObjectCollection.Add(Object) Method

定義

ListBox の項目のリストに項目を追加します。Adds an item to the list of items for a ListBox.

public:
 int Add(System::Object ^ item);
public int Add (object item);
member this.Add : obj -> int
Public Function Add (item As Object) As Integer

パラメーター

item
Object Object Object Object

コレクションに追加する項目を表すオブジェクト。An object representing the item to add to the collection.

戻り値

コレクション内の項目の 0 から始まるインデックス。BeginUpdate() が呼び出された場合は -1。The zero-based index of the item in the collection, or -1 if BeginUpdate() has been called.

実装

例外

新しい項目をリストに追加するための空き領域が不足しています。There is insufficient space available to add the new item to the list.

次のコード例は、作成する方法を示します、ListBoxコントロールの列に複数の項目を表示し、コントロールのリストで選択した 1 つ以上の項目を持つことができます。The following code example demonstrates how to create a ListBox control that displays multiple items in columns and can have more than one item selected in the control's list. 例のコードに 50 個の項目の追加、ListBoxを使用して、Addのメソッド、ListBox.ObjectCollectionを使用して、一覧から項目を 3 つのクラスと、選択、SetSelectedメソッド。The code for the example adds 50 items to the ListBox using the Add method of the ListBox.ObjectCollection class and then selects three items from the list using the SetSelected method. コードからの値を表示、ListBox.SelectedObjectCollectionコレクション (を通じて、SelectedItemsプロパティ) およびListBox.SelectedIndexCollection(を通じて、SelectedIndicesプロパティ)。The code then displays values from the ListBox.SelectedObjectCollection collection (through the SelectedItems property) and the ListBox.SelectedIndexCollection (through the SelectedIndices property). この例は、コードが記載されから呼び出すことが必要です、Formします。This example requires that the code is located in and called from a Form.

void button1_Click( Object^ /*sender*/, System::EventArgs^ /*e*/ )
{
   
   // Create an instance of the ListBox.
   ListBox^ listBox1 = gcnew ListBox;
   
   // Set the size and location of the ListBox.
   listBox1->Size = System::Drawing::Size( 200, 100 );
   listBox1->Location = System::Drawing::Point( 10, 10 );
   
   // Add the ListBox to the form.
   this->Controls->Add( listBox1 );
   
   // Set the ListBox to display items in multiple columns.
   listBox1->MultiColumn = true;
   
   // Set the selection mode to multiple and extended.
   listBox1->SelectionMode = SelectionMode::MultiExtended;
   
   // Shutdown the painting of the ListBox as items are added.
   listBox1->BeginUpdate();
   
   // Loop through and add 50 items to the ListBox.
   for ( int x = 1; x <= 50; x++ )
   {
      listBox1->Items->Add( String::Format( "Item {0}", x ) );

   }
   listBox1->EndUpdate();
   
   // Select three items from the ListBox.
   listBox1->SetSelected( 1, true );
   listBox1->SetSelected( 3, true );
   listBox1->SetSelected( 5, true );
   
   #if defined(DEBUG)
   // Display the second selected item in the ListBox to the console.
   System::Diagnostics::Debug::WriteLine( listBox1->SelectedItems[ 1 ] );
   
   // Display the index of the first selected item in the ListBox.
   System::Diagnostics::Debug::WriteLine( listBox1->SelectedIndices[ 0 ] );
   #endif
}

private void button1_Click(object sender, System.EventArgs e)
{
   // Create an instance of the ListBox.
   ListBox listBox1 = new ListBox();
   // Set the size and location of the ListBox.
   listBox1.Size = new System.Drawing.Size(200, 100);
   listBox1.Location = new System.Drawing.Point(10,10);
   // Add the ListBox to the form.
   this.Controls.Add(listBox1);
   // Set the ListBox to display items in multiple columns.
   listBox1.MultiColumn = true;
   // Set the selection mode to multiple and extended.
   listBox1.SelectionMode = SelectionMode.MultiExtended;
 
   // Shutdown the painting of the ListBox as items are added.
   listBox1.BeginUpdate();
   // Loop through and add 50 items to the ListBox.
   for (int x = 1; x <= 50; x++)
   {
      listBox1.Items.Add("Item " + x.ToString());
   }
   // Allow the ListBox to repaint and display the new items.
   listBox1.EndUpdate();
      
   // Select three items from the ListBox.
   listBox1.SetSelected(1, true);
   listBox1.SetSelected(3, true);
   listBox1.SetSelected(5, true);

   // Display the second selected item in the ListBox to the console.
   System.Diagnostics.Debug.WriteLine(listBox1.SelectedItems[1].ToString());
   // Display the index of the first selected item in the ListBox.
   System.Diagnostics.Debug.WriteLine(listBox1.SelectedIndices[0].ToString());             
}

Private Sub button1_Click(sender As Object, e As System.EventArgs)
    ' Create an instance of the ListBox.
    Dim listBox1 As New ListBox()
    ' Set the size and location of the ListBox.
    listBox1.Size = New System.Drawing.Size(200, 100)
    listBox1.Location = New System.Drawing.Point(10, 10)
    ' Add the ListBox to the form.
    Me.Controls.Add(listBox1)
    ' Set the ListBox to display items in multiple columns.
    listBox1.MultiColumn = True
    ' Set the selection mode to multiple and extended.
    listBox1.SelectionMode = SelectionMode.MultiExtended
    
    ' Shutdown the painting of the ListBox as items are added.
    listBox1.BeginUpdate()
    ' Loop through and add 50 items to the ListBox.
    Dim x As Integer
    For x = 1 To 50
        listBox1.Items.Add("Item " & x.ToString())
    Next x
    ' Allow the ListBox to repaint and display the new items.
    listBox1.EndUpdate()
    
    ' Select three items from the ListBox.
    listBox1.SetSelected(1, True)
    listBox1.SetSelected(3, True)
    listBox1.SetSelected(5, True)
       
    ' Display the second selected item in the ListBox to the console.
    System.Diagnostics.Debug.WriteLine(listBox1.SelectedItems(1).ToString())
    ' Display the index of the first selected item in the ListBox.
    System.Diagnostics.Debug.WriteLine(listBox1.SelectedIndices(0).ToString())
End Sub

注釈

場合、Sortedのプロパティ、ListBoxに設定されているtrue、アルファベット順に項目がリストに挿入します。If the Sorted property of the ListBox is set to true, the item is inserted into the list alphabetically. それ以外の場合、項目はリストの末尾に挿入されます。Otherwise, the item is inserted at the end of the list. 特定の位置にあるリスト ボックスには、項目を挿入するには、使用、Insertメソッド。To insert an item into the list box at a specific position, use the Insert method. 1 回の操作で、リスト ボックスには、一連の項目を追加するには、使用、AddRangeメソッド。To add a set of items to the list box in a single operation, use the AddRange method. 使用する場合、Addリストに多数のアイテムを追加、使用するメソッド、BeginUpdateEndUpdateようにする方法、ListBoxたびに再描画から項目が一覧に追加のすべての項目が一覧に追加されるまでです。If you want to use the Add method to add a large number of items to the list, use the BeginUpdate and EndUpdate methods to prevent the ListBox from repainting each time an item is added to the list until all items are added to the list. 項目を追加するときに、 ListBox、最初の項目の並べ替えし、新しい項目を追加する方が効率的です。When adding items to a ListBox, it is more efficient to sort the items first and then add new items.

オブジェクトがコレクションに追加されたときに、ListBoxかどうかを最初に確認、DisplayMemberのプロパティ、ListControlクラスには、項目のテキストを取得するときに参照を指定したオブジェクトからメンバーの名前。When an object is added to the collection, the ListBox first checks to see if the DisplayMember property of the ListControl class has the name of a member from the object specified to reference when obtaining the item text. 場合、DisplayMemberプロパティに指定すると、メンバーがない、ListBoxを呼び出して、ToStringメソッドの一覧に表示するテキストを取得するオブジェクト。If the DisplayMember property does not have a member specified, the ListBox then calls the ToString method of the object to obtain the text to display in the list.

適用対象