ListView.GetItemAt 方法

检索位于指定位置的项。

**命名空间:**System.Windows.Forms
**程序集:**System.Windows.Forms（在 system.windows.forms.dll 中）

语法

声明
Public Function GetItemAt ( _
    x As Integer, _
    y As Integer _
) As ListViewItem
用法
Dim instance As ListView
Dim x As Integer
Dim y As Integer
Dim returnValue As ListViewItem

returnValue = instance.GetItemAt(x, y)

public ListViewItem GetItemAt (
    int x,
    int y
)

public:
ListViewItem^ GetItemAt (
    int x, 
    int y
)

public ListViewItem GetItemAt (
    int x, 
    int y
)

public function GetItemAt (
    x : int, 
    y : int
) : ListViewItem

参数

• x
  项的搜索位置的 x 轴坐标（用工作区坐标表示）。

• y
  项的搜索位置的 y 轴坐标（用工作区坐标表示）。

返回值

ListViewItem，表示位于指定位置的项。如果指定的位置没有项，该方法返回 空引用（在 Visual Basic 中为 Nothing）。

备注

GetItemAt 方法使您可以确定哪个项位于 ListView 控件的工作区域中的特定位置。当用户单击或用鼠标右键单击子项（当 View 属性设置为 View.Details 时），并且您要在用户单击鼠标时根据鼠标坐标来确定是哪个项拥有被单击的子项时，可以使用该方法。

提示

当 FullRowSelect 属性值为 false 时，只有当指定位置位于父项（当控件处于详细信息模式时显示在第一列中的项）的边界之内时，此方法才会返回一个项。必须将 FullRowSelect 属性设置为 true 以使用此方法检索子项边界内给定位置上的项。还可以使用 HitTest 方法检索与特定位置上的项有关的详细信息。

若要使用拖放操作调整 ListView 中的项的位置，您可能需要使用 ListViewInsertionMark.NearestIndex 方法，而不是 GetItemAt 方法。ListViewInsertionMark.NearestIndex 方法查找位置最近的项，而无论鼠标指针的位置如何。另一方面，如果指定位置上不存在任何项，GetItemAt 方法将返回 空引用（在 Visual Basic 中为 Nothing）。

提示

如果应用程序调用 Application.EnableVisualStyles 方法，ListViewInsertionMark 类仅在 Windows XP 和 Windows Server 2003 上受支持。

示例

下面的代码示例演示 PictureBox 和 ListView 控件的用法。通过使用 BorderStyle 和 PictureBoxSizeMode 枚举分别设置 PictureBox.BorderStyle 和 PictureBox.SizeMode 属性来初始化 PictureBox。ListView 由 Samples 目录中的图片填充。当处理 ListView 控件的 MouseDown 事件时，将使用 GetItemAt 方法来确定某项是否被选定。如果某项被选定，事件处理程序将通过设置 PictureBox.Image 属性来显示选定的文件。该示例要求 C:\documents and Settings\All Users\Documents\My Pictures\Sample Pictures 目录中存在 JPG 文件。若要运行此示例，请将代码粘贴到一个窗体中，并在该窗体的构造函数或 Load 方法中调用 InitializePictureBox 和 PopulateListView 方法。确保所有事件都与其事件处理程序关联。

Private Sub PopulateListView()
    ListView1.Width = 270
    ListView1.Location = New System.Drawing.Point(10, 10)

    ' Declare and construct the ColumnHeader objects.
    Dim header1, header2 As ColumnHeader
    header1 = New ColumnHeader
    header2 = New ColumnHeader

    ' Set the text, alignment and width for each column header.
    header1.Text = "File name"
    header1.TextAlign = HorizontalAlignment.Left
    header1.Width = 70

    header2.TextAlign = HorizontalAlignment.Left
    header2.Text = "Location"
    header2.Width = 200

    ' Add the headers to the ListView control.
    ListView1.Columns.Add(header1)
    ListView1.Columns.Add(header2)

    ' Populate the ListView.Items property.
    ' Set the directory to the sample picture directory.
    Dim dirInfo As New System.IO.DirectoryInfo _
        ("C:\Documents and Settings\All Users" _
        & "\Documents\My Pictures\Sample Pictures")
    Dim file As System.IO.FileInfo

    ' Get the .jpg files from the directory
    Dim files() As System.io.FileInfo = dirInfo.GetFiles("*.jpg")

    ' Add each file name and full name including path
    ' to the ListView.
    If Not (files Is Nothing) Then
        For Each file In files
            Dim item As New ListViewItem(file.Name)
            item.SubItems.Add(file.FullName)
            ListView1.Items.Add(item)
        Next
    End If
End Sub

Private Sub InitializePictureBox()
    PictureBox1 = New PictureBox

    ' Set the location and size of the PictureBox control.
    Me.PictureBox1.Location = New System.Drawing.Point(70, 120)
    Me.PictureBox1.Size = New System.Drawing.Size(140, 140)
    Me.PictureBox1.TabStop = False

    ' Set the SizeMode property to the StretchImage value.  This
    ' will shrink or enlarge the image as needed to fit into
    ' the PictureBox.
    Me.PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage

    ' Set the border style to a three-dimensional border.
    Me.PictureBox1.BorderStyle = BorderStyle.Fixed3D

    ' Add the PictureBox to the form.
    Me.Controls.Add(Me.PictureBox1)

End Sub


Private Sub ListView1_MouseDown(ByVal sender As Object, _
    ByVal e As MouseEventArgs) Handles ListView1.MouseDown

    Dim selection As ListViewItem = ListView1.GetItemAt(e.X, e.Y)

    ' If the user selects an item in the ListView, display
    ' the image in the PictureBox.
    If Not (selection Is Nothing) Then
        PictureBox1.Image = System.Drawing.Image.FromFile _
            (selection.SubItems(1).Text)
    End If


End Sub

private void PopulateListView()
{
    ListView1.Width = 270;
    ListView1.Location = new System.Drawing.Point(10, 10);

    // Declare and construct the ColumnHeader objects.
    ColumnHeader header1, header2;
    header1 = new ColumnHeader();
    header2 = new ColumnHeader();

    // Set the text, alignment and width for each column header.
    header1.Text = "File name";
    header1.TextAlign = HorizontalAlignment.Left;
    header1.Width = 70;

    header2.TextAlign = HorizontalAlignment.Left;
    header2.Text = "Location";
    header2.Width = 200;

    // Add the headers to the ListView control.
    ListView1.Columns.Add(header1);
    ListView1.Columns.Add(header2);

    // Populate the ListView.Items property.
    // Set the directory to the sample picture directory.
    System.IO.DirectoryInfo dirInfo = 
        new System.IO.DirectoryInfo(
        "C:\\Documents and Settings\\All Users" +
        "\\Documents\\My Pictures\\Sample Pictures");
    

    // Get the .jpg files from the directory
    System.IO.FileInfo[] files = dirInfo.GetFiles("*.jpg");

    // Add each file name and full name including path
    // to the ListView.
    if (files != null)
    {
        foreach ( System.IO.FileInfo file in files )
        {
            ListViewItem item = new ListViewItem(file.Name);
            item.SubItems.Add(file.FullName);
            ListView1.Items.Add(item);
        }
    }
}

private void InitializePictureBox()
{
    PictureBox1 = new PictureBox();

    // Set the location and size of the PictureBox control.
    this.PictureBox1.Location = new System.Drawing.Point(70, 120);
    this.PictureBox1.Size = new System.Drawing.Size(140, 140);
    this.PictureBox1.TabStop = false;

    // Set the SizeMode property to the StretchImage value.  This
    // will shrink or enlarge the image as needed to fit into
    // the PictureBox.
    this.PictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;

    // Set the border style to a three-dimensional border.
    this.PictureBox1.BorderStyle = BorderStyle.Fixed3D;

    // Add the PictureBox to the form.
    this.Controls.Add(this.PictureBox1);

}


private void ListView1_MouseDown(object sender, MouseEventArgs e)
{

    ListViewItem selection = ListView1.GetItemAt(e.X, e.Y);

    // If the user selects an item in the ListView, display
    // the image in the PictureBox.
    if (selection != null)
    {
        PictureBox1.Image = System.Drawing.Image.FromFile(
            selection.SubItems[1].Text);
    }
}

private:
   void PopulateListView()
   {
      ListView1->Width = 270;
      ListView1->Location = System::Drawing::Point( 10, 10 );
      
      // Declare and construct the ColumnHeader objects.
      ColumnHeader^ header1;
      ColumnHeader^ header2;
      header1 = gcnew ColumnHeader;
      header2 = gcnew ColumnHeader;
      
      // Set the text, alignment and width for each column header.
      header1->Text = "File name";
      header1->TextAlign = HorizontalAlignment::Left;
      header1->Width = 70;
      header2->TextAlign = HorizontalAlignment::Left;
      header2->Text = "Location";
      header2->Width = 200;
      
      // Add the headers to the ListView control.
      ListView1->Columns->Add( header1 );
      ListView1->Columns->Add( header2 );
      
      // Populate the ListView.Items property.
      // Set the directory to the sample picture directory.
      System::IO::DirectoryInfo^ dirInfo = gcnew System::IO::DirectoryInfo( "C:\\Documents and Settings\\All Users"
      "\\Documents\\My Pictures\\Sample Pictures" );
      
      // Get the .jpg files from the directory
      array<System::IO::FileInfo^>^files = dirInfo->GetFiles( "*.jpg" );
      
      // Add each file name and full name including path
      // to the ListView.
      if ( files != nullptr )
      {
         System::Collections::IEnumerator^ myEnum = files->GetEnumerator();
         while ( myEnum->MoveNext() )
         {
            System::IO::FileInfo^ file = safe_cast<System::IO::FileInfo^>(myEnum->Current);
            ListViewItem^ item = gcnew ListViewItem( file->Name );
            item->SubItems->Add( file->FullName );
            ListView1->Items->Add( item );
         }
      }
   }

   void InitializePictureBox()
   {
      PictureBox1 = gcnew PictureBox;
      
      // Set the location and size of the PictureBox control.
      this->PictureBox1->Location = System::Drawing::Point( 70, 120 );
      this->PictureBox1->Size = System::Drawing::Size( 140, 140 );
      this->PictureBox1->TabStop = false;
      
      // Set the SizeMode property to the StretchImage value.  This
      // will shrink or enlarge the image as needed to fit into
      // the PictureBox.
      this->PictureBox1->SizeMode = PictureBoxSizeMode::StretchImage;
      
      // Set the border style to a three-dimensional border.
      this->PictureBox1->BorderStyle = BorderStyle::Fixed3D;
      
      // Add the PictureBox to the form.
      this->Controls->Add( this->PictureBox1 );
   }

   void ListView1_MouseDown( Object^ /*sender*/, MouseEventArgs^ e )
   {
      ListViewItem^ selection = ListView1->GetItemAt( e->X, e->Y );
      
      // If the user selects an item in the ListView, display
      // the image in the PictureBox.
      if ( selection != nullptr )
      {
         PictureBox1->Image = System::Drawing::Image::FromFile( selection->SubItems[ 1 ]->Text );
      }
   }

private void PopulateListView()
{
    listView1.set_Width(270);
    listView1.set_Location(new System.Drawing.Point(10, 10));
    // Declare and construct the ColumnHeader objects.
    ColumnHeader header1, header2;
    header1 = new ColumnHeader();
    header2 = new ColumnHeader();
    // Set the text, alignment and width for each column header.
    header1.set_Text("File name");
    header1.set_TextAlign(HorizontalAlignment.Left);
    header1.set_Width(70);

    header2.set_TextAlign(HorizontalAlignment.Left);
    header2.set_Text("Location");
    header2.set_Width(200);
    // Add the headers to the ListView control.
    listView1.get_Columns().Add(header1);
    listView1.get_Columns().Add(header2);
    // Populate the ListView.Items property.
    // Set the directory to the sample picture directory.
    System.IO.DirectoryInfo dirInfo =
        new System.IO.DirectoryInfo("C:\\Documents and Settings\\All Users"
        + "\\Documents\\My Pictures\\Sample Pictures");
    // Get the.jpg files from the directory
    System.IO.FileInfo files[] = dirInfo.GetFiles("*.jpg");
    // Add each file name and full name including path
    // to the ListView.
    if (files != null) {
        for (int iCtr = 0; iCtr < files.length; iCtr++) {
            System.IO.FileInfo file = files[iCtr];
            ListViewItem item = new ListViewItem(file.get_Name());
            item.get_SubItems().Add(file.get_FullName());
            listView1.get_Items().Add(item);
        }
    }
} //PopulateListView

private void InitializePictureBox()
{
    pictureBox1 = new PictureBox();
    // Set the location and size of the PictureBox control.
    this.pictureBox1.set_Location(new System.Drawing.Point(70, 120));
    this.pictureBox1.set_Size(new System.Drawing.Size(140, 140));
    this.pictureBox1.set_TabStop(false);
    // Set the SizeMode property to the StretchImage value.  This
    // will shrink or enlarge the image as needed to fit into
    // the PictureBox.
    this.pictureBox1.set_SizeMode(PictureBoxSizeMode.StretchImage);
    // Set the border style to a three-dimensional border.
    this.pictureBox1.set_BorderStyle(BorderStyle.Fixed3D);
    // Add the PictureBox to the form.
    this.get_Controls().Add(this.pictureBox1);
} //InitializePictureBox

private void listView1_MouseDown(Object sender, MouseEventArgs e)
{
    ListViewItem selection = listView1.GetItemAt(e.get_X(), e.get_Y());
    // If the user selects an item in the ListView, display
    // the image in the PictureBox.
    if (selection != null) {
        pictureBox1.set_Image(System.Drawing.Image.FromFile(
            selection.get_SubItems().get_Item(1).get_Text()));
    }
} //listView1_MouseDown

平台

Windows 98、Windows 2000 SP4、Windows CE、Windows Millennium Edition、Windows Mobile for Pocket PC、Windows Mobile for Smartphone、Windows Server 2003、Windows XP Media Center Edition、Windows XP Professional x64 Edition、Windows XP SP2、Windows XP Starter Edition

.NET Framework 并不是对每个平台的所有版本都提供支持。有关受支持版本的列表，请参见系统要求。

版本信息

.NET Framework

受以下版本支持：2.0、1.1、1.0

请参见

参考

ListView 类
ListView 成员
System.Windows.Forms 命名空间
PointToScreen
PointToClient
ListViewInsertionMark
ListViewItem
Application.EnableVisualStyles

其他资源

Windows 窗体坐标