ListBox.MeasureItem イベント
オーナー描画 ListBox が作成され、リスト項目のサイズが決定されると発生します。 名前空間: System.Windows.Forms
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文
解説
使用例
プラットフォーム
バージョン情報
参照
アセンブリ: System.Windows.Forms (system.windows.forms.dll 内)
構文Dim instance As ListBox Dim handler As MeasureItemEventHandler AddHandler instance.MeasureItem, handler
public: event MeasureItemEventHandler^ MeasureItem { void add (MeasureItemEventHandler^ value); void remove (MeasureItemEventHandler^ value); }
解説このイベントのイベント ハンドラを作成して、DrawItem イベントで項目が描画される前に、作成する項目のサイズを指定できます。このイベントは、DrawMode プロパティが OwnerDrawVariable に設定されている場合にだけ発生します。
ListBox の項目の有効な高さの最大値は 255 ピクセルです。このイベントの処理時に、MeasureItemEventArgs の ItemHeight プロパティを 255 を超える値に設定すると、予期しない結果が発生する場合があります。
使用例DrawMode プロパティを OwnerDrawVariable に設定し、DrawItem イベントおよび MeasureItem イベントを処理して、オーナー描画の ListBox を作成するコード例を次に示します。また、この例では、BorderStyle プロパティおよび ScrollAlwaysVisible プロパティを設定し、AddRange メソッドを使用しています。
この例を実行するには、System.Drawing 名前空間と System.Windows.Forms 名前空間をインポートした空のフォームにこのコードを貼り付けます。次に、フォームのコンストラクタまたは Load のイベント処理メソッドで InitializeOwnerDrawnListBox を呼び出します。
Friend WithEvents ListBox1 As System.Windows.Forms.ListBox Private Sub InitializeOwnerDrawnListBox() Me.ListBox1 = New System.Windows.Forms.ListBox ' Set the location and size. ListBox1.Location = New Point(20, 20) ListBox1.Size = New Size(240, 240) ' Populate the ListBox.ObjectCollection property ' with several strings, using the AddRange method. Me.ListBox1.Items.AddRange(New Object() _ {"System.Windows.Forms", "System.Drawing", "System.Xml", _ "System.Net", "System.Runtime.Remoting", "System.Web"}) ' Turn off the scrollbar. ListBox1.ScrollAlwaysVisible = False ' Set the border style to a single, flat border. ListBox1.BorderStyle = BorderStyle.FixedSingle ' Set the DrawMode property to the OwnerDrawVariable value. ' This means the MeasureItem and DrawItem events must be ' handled. ListBox1.DrawMode = DrawMode.OwnerDrawVariable Me.Controls.Add(Me.ListBox1) End Sub ' Handle the DrawItem event for an owner-drawn ListBox. Private Sub ListBox1_DrawItem(ByVal sender As Object, _ ByVal e As DrawItemEventArgs) Handles ListBox1.DrawItem ' If the item is the selected item, then draw the rectangle filled in ' blue. The item is selected when a bitwise And of the State property ' and the DrawItemState.Selected property is true. If (e.State And DrawItemState.Selected = DrawItemState.Selected) Then e.Graphics.FillRectangle(Brushes.CornflowerBlue, e.Bounds) Else ' Otherwise, draw the rectangle filled in beige. e.Graphics.FillRectangle(Brushes.Beige, e.Bounds) End If ' Draw a rectangle in blue around each item. e.Graphics.DrawRectangle(Pens.Blue, e.Bounds) ' Draw the text in the item. e.Graphics.DrawString(Me.ListBox1.Items(e.Index), Me.Font, _ Brushes.Black, e.Bounds.X, e.Bounds.Y) ' Draw the focus rectangle around the selected item. e.DrawFocusRectangle() End Sub ' Handle the MeasureItem event for an owner-drawn ListBox. Private Sub ListBox1_MeasureItem(ByVal sender As Object, _ ByVal e As MeasureItemEventArgs) Handles ListBox1.MeasureItem ' Cast the sender object back to ListBox type. Dim theListBox As ListBox = CType(sender, ListBox) ' Get the string contained in each item. Dim itemString As String = CType(theListBox.Items(e.Index), String) ' Split the string at the " . " character. Dim resultStrings() As String = itemString.Split(".") ' If the string contains more than one period, increase the ' height by ten pixels; otherwise, increase the height by ' five pixels. If (resultStrings.Length > 2) Then e.ItemHeight += 10 Else e.ItemHeight += 5 End If End Sub
internal System.Windows.Forms.ListBox ListBox1; private void InitializeOwnerDrawnListBox() { this.ListBox1 = new System.Windows.Forms.ListBox(); // Set the location and size. ListBox1.Location = new Point(20, 20); ListBox1.Size = new Size(240, 240); // Populate the ListBox.ObjectCollection property // with several strings, using the AddRange method. this.ListBox1.Items.AddRange(new object[]{"System.Windows.Forms", "System.Drawing", "System.Xml", "System.Net", "System.Runtime.Remoting", "System.Web"}); // Turn off the scrollbar. ListBox1.ScrollAlwaysVisible = false; // Set the border style to a single, flat border. ListBox1.BorderStyle = BorderStyle.FixedSingle; // Set the DrawMode property to the OwnerDrawVariable value. // This means the MeasureItem and DrawItem events must be // handled. ListBox1.DrawMode = DrawMode.OwnerDrawVariable; ListBox1.MeasureItem += new MeasureItemEventHandler(ListBox1_MeasureItem); ListBox1.DrawItem += new DrawItemEventHandler(ListBox1_DrawItem); this.Controls.Add(this.ListBox1); } // Handle the DrawItem event for an owner-drawn ListBox. private void ListBox1_DrawItem(object sender, DrawItemEventArgs e) { // If the item is the selected item, then draw the rectangle // filled in blue. The item is selected when a bitwise And // of the State property and the DrawItemState.Selected // property is true. if ((e.State & DrawItemState.Selected) == DrawItemState.Selected) { e.Graphics.FillRectangle(Brushes.CornflowerBlue, e.Bounds); } else { // Otherwise, draw the rectangle filled in beige. e.Graphics.FillRectangle(Brushes.Beige, e.Bounds); } // Draw a rectangle in blue around each item. e.Graphics.DrawRectangle(Pens.Blue, e.Bounds); // Draw the text in the item. e.Graphics.DrawString(ListBox1.Items[e.Index].ToString(), this.Font, Brushes.Black, e.Bounds.X, e.Bounds.Y); // Draw the focus rectangle around the selected item. e.DrawFocusRectangle(); } // Handle the MeasureItem event for an owner-drawn ListBox. private void ListBox1_MeasureItem(object sender, MeasureItemEventArgs e) { // Cast the sender object back to ListBox type. ListBox theListBox = (ListBox) sender; // Get the string contained in each item. string itemString = (string) theListBox.Items[e.Index]; // Split the string at the " . " character. string[] resultStrings = itemString.Split('.'); // If the string contains more than one period, increase the // height by ten pixels; otherwise, increase the height by // five pixels. if (resultStrings.Length>2) { e.ItemHeight += 10; } else { e.ItemHeight += 5; } }
internal: System::Windows::Forms::ListBox^ ListBox1; private: void InitializeOwnerDrawnListBox() { this->ListBox1 = gcnew System::Windows::Forms::ListBox; // Set the location and size. ListBox1->Location = Point(20,20); ListBox1->Size = System::Drawing::Size( 240, 240 ); // Populate the ListBox.ObjectCollection property // with several strings, using the AddRange method. array<Object^>^temp0 = {"System.Windows.Forms","System.Drawing" ,"System.Xml","System.Net","System.Runtime.Remoting" ,"System.Web"}; this->ListBox1->Items->AddRange( temp0 ); // Turn off the scrollbar. ListBox1->ScrollAlwaysVisible = false; // Set the border style to a single, flat border. ListBox1->BorderStyle = BorderStyle::FixedSingle; // Set the DrawMode property to the OwnerDrawVariable value. // This means the MeasureItem and DrawItem events must be // handled. ListBox1->DrawMode = DrawMode::OwnerDrawVariable; ListBox1->MeasureItem += gcnew MeasureItemEventHandler( this, &Form1::ListBox1_MeasureItem ); ListBox1->DrawItem += gcnew DrawItemEventHandler( this, &Form1::ListBox1_DrawItem ); this->Controls->Add( this->ListBox1 ); } // Handle the DrawItem event for an owner-drawn ListBox. void ListBox1_DrawItem( Object^ /*sender*/, DrawItemEventArgs^ e ) { // If the item is the selected item, then draw the rectangle // filled in blue. The item is selected when a bitwise And // of the State property and the DrawItemState.Selected // property is true. if ( (e->State & DrawItemState::Selected) == DrawItemState::Selected ) { e->Graphics->FillRectangle( Brushes::CornflowerBlue, e->Bounds ); } else { // Otherwise, draw the rectangle filled in beige. e->Graphics->FillRectangle( Brushes::Beige, e->Bounds ); } // Draw a rectangle in blue around each item. e->Graphics->DrawRectangle( Pens::Blue, e->Bounds ); // Draw the text in the item. e->Graphics->DrawString( ListBox1->Items[ e->Index ]->ToString(), this->Font, Brushes::Black, (float)e->Bounds.X, (float)e->Bounds.Y ); // Draw the focus rectangle around the selected item. e->DrawFocusRectangle(); } // Handle the MeasureItem event for an owner-drawn ListBox. void ListBox1_MeasureItem( Object^ sender, MeasureItemEventArgs^ e ) { // Cast the sender object back to ListBox type. ListBox^ theListBox = dynamic_cast<ListBox^>(sender); // Get the string contained in each item. String^ itemString = dynamic_cast<String^>(theListBox->Items[ e->Index ]); // Split the string at the " . " character. array<Char>^temp1 = {'.'}; array<String^>^resultStrings = itemString->Split( temp1 ); // If the string contains more than one period, increase the // height by ten pixels; otherwise, increase the height by // five pixels. if ( resultStrings->Length > 2 ) { e->ItemHeight += 10; } else { e->ItemHeight += 5; } }
private System.Windows.Forms.ListBox listBox1; private void InitializeOwnerDrawnListBox() { this.listBox1 = new System.Windows.Forms.ListBox(); // Set the location and size. listBox1.set_Location(new Point(20, 20)); listBox1.set_Size(new Size(240, 240)); // Populate the ListBox.ObjectCollection property // with several strings, using the AddRange method. this.listBox1.get_Items().AddRange(new Object[] { "System.Windows.Forms", "System.Drawing", "System.Xml", "System.Net", "System.Runtime.Remoting", "System.Web" }); // Turn off the scrollbar. listBox1.set_ScrollAlwaysVisible(false); // Set the border style to a single, flat border. listBox1.set_BorderStyle(BorderStyle.FixedSingle); // Set the DrawMode property to the OwnerDrawVariable value. // This means the MeasureItem and DrawItem events must be // handled. listBox1.set_DrawMode(DrawMode.OwnerDrawVariable); listBox1.add_MeasureItem(new MeasureItemEventHandler( listBox1_MeasureItem)); listBox1.add_DrawItem(new DrawItemEventHandler(listBox1_DrawItem)); this.get_Controls().Add(this.listBox1); } //InitializeOwnerDrawnListBox // Handle the DrawItem event for an owner-drawn ListBox. private void listBox1_DrawItem(Object sender, DrawItemEventArgs e) { // If the item is the selected item, then draw the rectangle // filled in blue. The item is selected when a bitwise And // of the State property and the DrawItemState.Selected // property is true. if ((e.get_State() & DrawItemState.Selected) == DrawItemState.Selected) { e.get_Graphics().FillRectangle(Brushes.get_CornflowerBlue(), e.get_Bounds()); } else { // Otherwise, draw the rectangle filled in beige. e.get_Graphics().FillRectangle(Brushes.get_Beige(), e.get_Bounds()); } // Draw a rectangle in blue around each item. e.get_Graphics().DrawRectangle(Pens.get_Blue(), e.get_Bounds()); // Draw the text in the item. e.get_Graphics().DrawString(listBox1.get_Items().get_Item( e.get_Index()).ToString(), this.get_Font(), Brushes.get_Black(), e.get_Bounds().get_X(), e.get_Bounds().get_Y()); // Draw the focus rectangle around the selected item. e.DrawFocusRectangle(); } //listBox1_DrawItem // Handle the MeasureItem event for an owner-drawn ListBox. private void listBox1_MeasureItem(Object sender, MeasureItemEventArgs e) { // Cast the sender object back to ListBox type. ListBox theListBox = (ListBox) sender; // Get the string contained in each item. String itemString = (String)(theListBox.get_Items(). get_Item(e.get_Index())); // Split the string at the " . " character. String resultStrings[] = itemString.Split(new char[] { '.' }); // If the string contains more than one period, increase the // height by ten pixels; otherwise, increase the height by // five pixels. if (resultStrings.length > 2) { e.set_ItemHeight(e.get_ItemHeight() + 10); } else { e.set_ItemHeight(e.get_ItemHeight() + 5); } } //listBox1_MeasureItem
プラットフォームWindows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
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バージョン情報参照- ListBox.MeasureItem イベントのページへのリンク
