blog:2025-04-15-001
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blog:2025-04-15-001 [2025/04/15 13:45] (current) jethro created |
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| + | ~~NOTOC~~ | ||
| + | ====== 2025-04-15 c# contextmenustrip 關聯之listbox ====== | ||
| + | * 在 C# 中，可以使用 ContextMenuStrip 來實現根據 ListBox 的選擇狀態顯示不同的選單項目。以下是一個簡單的範例，說明如何根據 ListBox 的選擇狀態來顯示 "Add" 和 "Delete" 菜單項目。 | ||
| + | ===== 步驟 ===== | ||
| + | * 建立一個 Windows Forms 應用程式。 | ||
| + | * 添加 ListBox 和 ContextMenuStrip 控制項。 | ||
| + | * 設置 ContextMenuStrip 的事件。 | ||
| + | ===== 範例程式碼 ===== | ||
| + | * <sxh c#>using System; | ||
| + | using System.Windows.Forms; | ||
| + | |||
| + | public class MyForm : Form | ||
| + | { | ||
| + | private ListBox listBox; | ||
| + | private ContextMenuStrip contextMenuStrip; | ||
| + | |||
| + | public MyForm() | ||
| + | { | ||
| + | listBox = new ListBox(); | ||
| + | contextMenuStrip = new ContextMenuStrip(); | ||
| + | |||
| + | // 添加菜單項目 | ||
| + | ToolStripMenuItem addItem = new ToolStripMenuItem("Add"); | ||
| + | ToolStripMenuItem deleteItem = new ToolStripMenuItem("Delete"); | ||
| + | |||
| + | // 將菜單項目添加到 ContextMenuStrip | ||
| + | contextMenuStrip.Items.Add(addItem); | ||
| + | contextMenuStrip.Items.Add(deleteItem); | ||
| + | |||
| + | // 將 ContextMenuStrip 關聯到 ListBox | ||
| + | listBox.ContextMenuStrip = contextMenuStrip; | ||
| + | |||
| + | // 設置事件處理 | ||
| + | listBox.MouseDown += ListBox_MouseDown; | ||
| + | | ||
| + | // 添加 ListBox 到窗體 | ||
| + | listBox.Dock = DockStyle.Fill; | ||
| + | this.Controls.Add(listBox); | ||
| + | | ||
| + | // 添加一些示例項目 | ||
| + | listBox.Items.Add("Item 1"); | ||
| + | listBox.Items.Add("Item 2"); | ||
| + | listBox.Items.Add("Item 3"); | ||
| + | } | ||
| + | |||
| + | private void ListBox_MouseDown(object sender, MouseEventArgs e) | ||
| + | { | ||
| + | if (e.Button == MouseButtons.Right) | ||
| + | { | ||
| + | // 獲取選中的項目 | ||
| + | int index = listBox.IndexFromPoint(e.Location); | ||
| + | if (index != -1) // 有選中項目 | ||
| + | { | ||
| + | contextMenuStrip.Items[1].Visible = true; // 顯示 Delete | ||
| + | } | ||
| + | else // 沒有選中項目 | ||
| + | { | ||
| + | contextMenuStrip.Items[1].Visible = false; // 隱藏 Delete | ||
| + | } | ||
| + | } | ||
| + | } | ||
| + | |||
| + | [STAThread] | ||
| + | static void Main() | ||
| + | { | ||
| + | Application.EnableVisualStyles(); | ||
| + | Application.Run(new MyForm()); | ||
| + | } | ||
| + | }</sxh> | ||
| + | ===== 說明 ===== | ||
| + | * ListBox: 用於顯示項目。 | ||
| + | * ContextMenuStrip: 包含 "Add" 和 "Delete" 菜單項目。 | ||
| + | * MouseDown 事件: 當右鍵單擊 ListBox 時，檢查是否有選中的項目，並根據選擇狀態顯示或隱藏 "Delete" 菜單項目。 | ||
| + | ===== 注意事項 ===== | ||
| + | * 確保將 ContextMenuStrip 的 Visible 屬性設置為 true 或 false，以控制菜單項目的顯示。 | ||
| + | * 可以根據需求添加 "Add" 菜單項目的功能。 | ||
| + | * 這樣就可以根據 ListBox 的選擇狀態來顯示不同的上下文菜單了！ | ||
| + | ===== TAGS ===== | ||
| + | * | ||
| + | ====== ====== | ||
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| + | ====== ====== | ||
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| + | Code Highlight: <sxh php; first-line: 70; highlight: [89,92]; title: New title attribute in action> | ||
| + | |||
| + | --></html> | ||
blog/2025-04-15-001.txt · Last modified: 2025/04/15 13:45 by jethro
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