ListViewItem.Group 属性

定义

命名空间:

System.Windows.Forms

程序集:

System.Windows.Forms.dll

获取或设置该项所分配到的组。

public:
 property System::Windows::Forms::ListViewGroup ^ Group { System::Windows::Forms::ListViewGroup ^ get(); void set(System::Windows::Forms::ListViewGroup ^ value); };

public System.Windows.Forms.ListViewGroup? Group { get; set; }

member this.Group : System.Windows.Forms.ListViewGroup with get, set

Public Property Group As ListViewGroup

属性值

ListViewGroup

该项所分配到的 ListViewGroup。

示例

下面的代码示例演示如何 Group 在按详细信息视图中的子项值组织 ListView 项的应用程序中使用 属性。 这种形式的分组类似于 Windows 资源管理器中使用的分组。 在此示例中，组是动态创建的。 对于每个子项列，为每个唯一的子项值创建一个组。 对于父项列，为每个唯一的首字母创建一个组。 为每个列创建的组与子项文本或首字母一起存储在哈希表中。 单击列标题时，将检索与该列对应的哈希表。 接下来，该列的子项文本值用作哈希表键，以检索每个项的正确组。 然后，使用 Group 属性将项分配给组。

此代码示例是为 属性提供的更大示例的 ListView.Groups 一部分。

   // Sets myListView to the groups created for the specified column.
private:
   void SetGroups(int column)
   {
      // Remove the current groups.
      myListView->Groups->Clear();

      // Retrieve the hash table corresponding to the column.
      Hashtable^ groups = dynamic_cast<Hashtable^>(groupTables[column]);

      // Copy the groups for the column to an array.
      array<ListViewGroup^>^ groupsArray = gcnew array<ListViewGroup^>(groups->Count);
      groups->Values->CopyTo(groupsArray, 0);

      // Sort the groups and add them to myListView.
      Array::Sort(groupsArray, gcnew ListViewGroupSorter(myListView->Sorting));
      myListView->Groups->AddRange(groupsArray);

      // Iterate through the items in myListView, assigning each 
      // one to the appropriate group.
      IEnumerator^ myEnum = myListView->Items->GetEnumerator();
      while (myEnum->MoveNext())
      {
         ListViewItem^ item = safe_cast<ListViewItem^>(myEnum->Current);
         // Retrieve the subitem text corresponding to the column.
         String^ subItemText = item->SubItems[column]->Text;

         // For the Title column, use only the first letter.
         if (column == 0) 
         {
            subItemText = subItemText->Substring(0, 1);
         }

         // Assign the item to the matching group.
         item->Group = dynamic_cast<ListViewGroup^>(groups[subItemText]);
      }
   }

// Sets myListView to the groups created for the specified column.
private void SetGroups(int column)
{
    // Remove the current groups.
    myListView.Groups.Clear();

    // Retrieve the hash table corresponding to the column.
    Hashtable groups = (Hashtable)groupTables[column];

    // Copy the groups for the column to an array.
    ListViewGroup[] groupsArray = new ListViewGroup[groups.Count];
    groups.Values.CopyTo(groupsArray, 0);

    // Sort the groups and add them to myListView.
    Array.Sort(groupsArray, new ListViewGroupSorter(myListView.Sorting));
    myListView.Groups.AddRange(groupsArray);

    // Iterate through the items in myListView, assigning each 
    // one to the appropriate group.
    foreach (ListViewItem item in myListView.Items)
    {
        // Retrieve the subitem text corresponding to the column.
        string subItemText = item.SubItems[column].Text;

        // For the Title column, use only the first letter.
        if (column == 0) 
        {
            subItemText = subItemText.Substring(0, 1);
        }

        // Assign the item to the matching group.
        item.Group = (ListViewGroup)groups[subItemText];
    }
}

' Sets myListView to the groups created for the specified column.
Private Sub SetGroups(column As Integer)
    ' Remove the current groups.
    myListView.Groups.Clear()
    
    ' Retrieve the hash table corresponding to the column.
    Dim groups As Hashtable = CType(groupTables(column), Hashtable)
    
    ' Copy the groups for the column to an array.
    Dim groupsArray(groups.Count - 1) As ListViewGroup
    groups.Values.CopyTo(groupsArray, 0)
    
    ' Sort the groups and add them to myListView.
    Array.Sort(groupsArray, New ListViewGroupSorter(myListView.Sorting))
    myListView.Groups.AddRange(groupsArray)
    
    ' Iterate through the items in myListView, assigning each 
    ' one to the appropriate group.
    Dim item As ListViewItem
    For Each item In myListView.Items
        ' Retrieve the subitem text corresponding to the column.
        Dim subItemText As String = item.SubItems(column).Text
        
        ' For the Title column, use only the first letter.
        If column = 0 Then
            subItemText = subItemText.Substring(0, 1)
        End If 

        ' Assign the item to the matching group.
        item.Group = CType(groups(subItemText), ListViewGroup)
    Next item
End Sub

注解

使用此属性可设置项所属的组。 还可以在构造函数中 ListViewItem 设置组，也可以使用此属性在运行时修改组成员身份。 如果将此属性设置为 null ，并且集合中有 ListView.Groups 组，则该项将显示在具有标题标签“DefaultGroupSystem.Windows.Forms”的默认组中。 默认组不包含在集合中 ListView.Groups ，并且无法更改。 它主要用于调试，以确保所有项都已正确添加到组。

注意

ListView 组仅适用于 Windows XP 和 Windows Server 2003 系列 (Windows XP Home Edition、Windows XP Professional、Windows Server 2003) 。 有关更多信息，请参见 ListViewGroup 概述主题。

另请参阅

• ListViewGroup