如何向 ListBoxItem 添加上下文菜單？

Question

我有一個 ListBox，我想為列表中的每個項目添加一個上下文菜單。 我已經看到“解決方案”讓右鍵單擊選擇一個項目並在空白處取消上下文菜單，但是這個解決方案感覺很臟。

有人知道更好的方法嗎？

Answer 1

只是為了進一步詳細說明 Frans 所說的內容...即使 ListBox 擁有 ContextMenuStrip，您仍然可以在打開菜單條時自定義菜單條中的項目。 因此根據列表框中的鼠標位置自定義其內容。

下面的示例基於鼠標右鍵單擊選擇列表框中的項目，然后根據用戶右鍵單擊的項目自定義上下文菜單條。 這是一個簡單的示例，但應該可以幫助您：將列表框添加到表單並添加以下代碼：

#region Private Members
private ContextMenuStrip listboxContextMenu;
#endregion

private void Form1_Load( object sender, EventArgs e )
{
    //assign a contextmenustrip
    listboxContextMenu = new ContextMenuStrip();
    listboxContextMenu.Opening +=new CancelEventHandler(listboxContextMenu_Opening);
    listBox1.ContextMenuStrip = listboxContextMenu;

    //load a listbox
    for ( int i = 0; i < 100; i++ )
    {
        listBox1.Items.Add( "Item: " + i );
    }
}

private void listBox1_MouseDown( object sender, MouseEventArgs e )
{
    if ( e.Button == MouseButtons.Right )
    {
        //select the item under the mouse pointer
        listBox1.SelectedIndex = listBox1.IndexFromPoint( e.Location );
        if ( listBox1.SelectedIndex != -1)
        {
            listboxContextMenu.Show();   
        }                
    }
}

private void listboxContextMenu_Opening( object sender, CancelEventArgs e )
{
    //clear the menu and add custom items
    listboxContextMenu.Items.Clear();
    listboxContextMenu.Items.Add( string.Format( "Edit - {0}", listBox1.SelectedItem.ToString() ) );
}

希望有所幫助。

Answer 2

這樣菜單就會在鼠標旁邊彈出

private string _selectedMenuItem;
private readonly ContextMenuStrip collectionRoundMenuStrip;

public Form1()
{ 
    var toolStripMenuItem1 = new ToolStripMenuItem {Text = "Copy CR Name"};
    toolStripMenuItem1.Click += toolStripMenuItem1_Click;
    var toolStripMenuItem2 = new ToolStripMenuItem {Text = "Get information on CR"};
    toolStripMenuItem2.Click += toolStripMenuItem2_Click;
    collectionRoundMenuStrip = new ContextMenuStrip();
    collectionRoundMenuStrip.Items.AddRange(new ToolStripItem[] {toolStripMenuItem1, toolStripMenuItem2 });
    listBoxCollectionRounds.MouseDown += listBoxCollectionRounds_MouseDown;
}

private void toolStripMenuItem2_Click(object sender, EventArgs e)
{
    var info = GetInfoByName(_selectedMenuItem);
   MessageBox.Show(info.Name + Environment.NewLine + info.Date);
}

private void toolStripMenuItem1_Click(object sender, EventArgs e)
{
    Clipboard.SetText(_selectedMenuItem);
}

private void myListBox_MouseDown(object sender, MouseEventArgs e)
{
    if (e.Button != MouseButtons.Right) return;
    var index = myListBox.IndexFromPoint(e.Location);
    if (index != ListBox.NoMatches)
    {
        _selectedMenuItem = listBoxCollectionRounds.Items[index].ToString();
        collectionRoundMenuStrip.Show(Cursor.Position);
        collectionRoundMenuStrip.Visible = true;
    }
    else
    {
        collectionRoundMenuStrip.Visible = false;
    }
}

Answer 3

這是我的解決方案：

listBox_Usernames.ContextMenuStrip = contextMenuStripRemove;
listBox_Usernames.MouseUp += new MouseEventHandler(listBox_Usernames_MouseUp);

void listBox_Usernames_MouseUp(object sender, MouseEventArgs e)
{
    int index = listBox_Usernames.IndexFromPoint(e.Location);
    if (e.Button == System.Windows.Forms.MouseButtons.Right)
    {
        if (index != ListBox.NoMatches)
        {
            if (listBox_Usernames.SelectedIndex == index)
            {
                listBox_Usernames.ContextMenuStrip.Visible = true;
            }
            else
            {
                listBox_Usernames.ContextMenuStrip.Visible = false;
            }
        }
        else
        {
            listBox_Usernames.ContextMenuStrip.Visible = false;
        }
    }
    else
    {
        listBox_Usernames.ContextMenuStrip.Visible = false;
    }
}

Answer 4

沒有其他方法：上下文菜單不屬於列表框中的項目，而是屬於列表框本身。 它類似於樹視圖控件，它也擁有上下文菜單而不是樹節點。 因此，只要選中“列表”框中的項目，根據所選項目設置ListBox的上下文菜單。

Answer 5

在 XAML 中，它顯示如下：

 <ListBox> <ListBox.ContextMenu> <ContextMenu> <MenuItem Header="Add User..."/> <MenuItem Header="Edit..."/> <MenuItem Header="Disable"/> </ContextMenu> </ListBox.ContextMenu> </ListBox>

Answer 6

在一行代碼中（更多用於綁定）：

var datasource = new BindingList<string>( new List<string>( new string[] { "item1" } ) );
listbox.DataSource = datasource ;
listbox.ContextMenu = new ContextMenu(
    new MenuItem[] { 
        new MenuItem("Delete", 
            new EventHandler( (s,ev) => 
            datasource.Remove(listbox.SelectedItem.ToString())
        )
    ) 
});

private void buttonAdd_Click(object sender, EventArgs e)
{
    datasource.Add( textBox.Text );
}   

Answer 7

這個最好...

using System.Windows.Forms;

ContextMenuStrip menu;

this.menu.Items.AddRange(new ToolStripItem[] { this.menuItem });
this.listBox.MouseUp += new MouseEventHandler(this.mouse_RightClick);

private void mouse_RightClick(object sender, MouseEventArgs e)
{
    int index = this.listBox.IndexFromPoint(e.Location);
    if (index != ListBox.NoMatches)
    {
        menu.Visible = true;
    }
    else
    {
        menu.Visible = false;
    }
}

Answer 8

如果只是啟用或禁用上下文菜單項的問題，那么僅在上下文菜單啟動時執行此操作可能更有效，而不是每次列表框選擇更改時執行此操作：

myListBox.ContextMenu.Popup += new EventHandler(myContextPopupHandler);


private void myContextPopupHandler(Object sender, System.EventArgs e)
{
    if (SelectedItem != null)
    {
        ContextMenu.MenuItems[1].Enabled = true;
        ContextMenu.MenuItems[2].Enabled = true;
    }
    else
    {
        ContextMenu.MenuItems[1].Enabled = false;
        ContextMenu.MenuItems[2].Enabled = false;
    }
}

Answer 9

//Create and Initialize the contextMenuStrip component
contextMenuStrip_ListaAulas = new ContextMenuStrip();

//Adding an Item
contextMenuStrip_ListaAulas.Items.Add("Modificar");

//Binding the contextMenuStrip with the ListBox
listBox_Aulas.ContextMenuStrip = contextMenuStrip_ListaAulas;

//The solution below 
if (e.Button == System.Windows.Forms.MouseButtons.Right)
{
    //select the item under the mouse pointer
    listBox_Aulas.SelectedIndex = listBox_Aulas.IndexFromPoint(e.Location);

    //if the selected index is an item, binding the context MenuStrip with the listBox
    if (listBox_Aulas.SelectedIndex != -1)
    {
         listBox_Aulas.ContextMenuStrip = contextMenuStrip_ListaAulas;  
    }
    //else, untie the contextMenuStrip to the listBox 
    else
    {
         listBox_Aulas.ContextMenuStrip = null;
    }
}

Answer 10

我喜歡這個，這對我來說效果很好而且速度很快。

private void contextMenuStrip1_Opening(object sender, CancelEventArgs e)
    {
        if (Listbox.SelectedItem == null)
            e.Cancel = true;
    }