TextBox.Paste 事件

定义

命名空间:

Windows.UI.Xaml.Controls

将文本粘贴到 控件中时发生。

public:
 virtual event TextControlPasteEventHandler ^ Paste;

// Register
event_token Paste(TextControlPasteEventHandler const& handler) const;

// Revoke with event_token
void Paste(event_token const* cookie) const;

// Revoke with event_revoker
TextBox::Paste_revoker Paste(auto_revoke_t, TextControlPasteEventHandler const& handler) const;

public event TextControlPasteEventHandler Paste;

function onPaste(eventArgs) { /* Your code */ }
textBox.addEventListener("paste", onPaste);
textBox.removeEventListener("paste", onPaste);
- or -
textBox.onpaste = onPaste;

Public Custom Event Paste As TextControlPasteEventHandler 

<TextBox Paste="eventhandler"/>

事件类型

TextControlPasteEventHandler

示例

此示例演示如何处理 Paste 事件，以在粘贴到地址字段中时用逗号替换换行符。 否则，粘贴从多行复制的地址将导致数据丢失。

<TextBox Header="Address" Paste="AddressTextBox_Paste"/>

private async void AddressTextBox_Paste(object sender, TextControlPasteEventArgs e)
{
    TextBox addressBox = sender as TextBox;
    if (addressBox != null)
    {
        // Mark the event as handled first. Otherwise, the
        // default paste action will happen, then the custom paste
        // action, and the user will see the text box content change.
        e.Handled = true;

        // Get content from the clipboard.
        var dataPackageView = Windows.ApplicationModel.DataTransfer.Clipboard.GetContent();
        if (dataPackageView.Contains(Windows.ApplicationModel.DataTransfer.StandardDataFormats.Text))
        {
            try
            {
                var text = await dataPackageView.GetTextAsync();

                // Remove line breaks from multi-line text and
                // replace with comma(,).
                string singleLineText = text.Replace("\r\n", ", ");

                // Replace any text currently in the text box.
                addressBox.Text = singleLineText;
            }
            catch (Exception)
            {
                // Ignore or handle exception as needed.
            }
        }
    }
}

此示例演示如何处理 Paste 事件以限制粘贴到 TextBox 中的字符数。 如果剪贴板上的文本长度超过 TextBox 的 MaxLength，则会向用户显示一条消息。 用户可以选择继续截断文本，或取消粘贴操作。

<TextBox Paste="TextBox_Paste" MaxLength="10"/>

private async void TextBox_Paste(object sender, TextControlPasteEventArgs e)
{
    TextBox tb = sender as TextBox;
    if (tb != null)
    {
        // Mark the event as handled first. Otherwise, the
        // default paste action will happen, then the custom paste
        // action, and the user will see the text box content change.
        e.Handled = true;

        // Get content from the clipboard.
        var dataPackageView = Windows.ApplicationModel.DataTransfer.Clipboard.GetContent();
        if (dataPackageView.Contains(Windows.ApplicationModel.DataTransfer.StandardDataFormats.Text))
        {
            try
            {
                var text = await dataPackageView.GetTextAsync();
                if (text.Length > tb.MaxLength)
                {
                    // Pasted text is too long. Show a message to the user.
                    // Create the message dialog and set its content
                    var messageDialog = 
                        new Windows.UI.Popups.MessageDialog(
                            "Pasted text excedes maximum allowed (" 
                            + tb.MaxLength.ToString() + 
                            " characters). The text will be truncated.");

                    // Add commands to the message dialog.
                    messageDialog.Commands.Add(new UICommand("Continue", (command) =>
                    {
                        // Truncate the text to be pasted to the MaxLength of the text box.
                        string truncatedText = text.Substring(0, tb.MaxLength);
                        tb.Text = truncatedText;
                    }));
                    messageDialog.Commands.Add(new UICommand("Cancel", (command) =>
                    {
                        // Cancelled. Do nothing.
                    }));

                    // Set the command that will be invoked by default.
                    messageDialog.DefaultCommandIndex = 0;

                    // Set the command to be invoked when escape is pressed.
                    messageDialog.CancelCommandIndex = 1;

                    // Show the message dialog.
                    await messageDialog.ShowAsync();
                }
                else
                {
                    tb.Text = text;
                }                          
            }
            catch (Exception)
            {
                // Ignore or handle exception as needed.
            }
        }
    }
}

注解

粘贴事件在将任何内容插入控件之前发生。 可以处理此事件以检查剪贴板的内容，并在插入内容之前对内容执行任何操作。 如果执行任何操作，请将事件参数的 Handled 属性设置为 true;否则，将执行默认粘贴操作。 如果将事件标记为已处理，则假定应用已处理粘贴操作，并且不会执行任何默认操作。 你负责确定要插入的插入点和剪贴板内容，并插入内容。

在代码执行自定义粘贴操作之前，应在处理程序中将 Handled 属性设置为 true 。 否则，将执行默认粘贴操作，然后执行自定义操作。 用户可以在 TextBox 中看到内容发生更改。