处理在C＃中粘贴事件 [英] Handle a paste event in c#

问题描述

我创建了一个静态类数字文本框，但我wan't控制哪些用户粘贴德文本框。 为了处理粘贴事件中，我使用TextChanged事件：

I've created a static class numeric Textbox but i wan't to control what the users paste in te textbox. For handling paste Event i use textchanged event:

        static public void textChanged(EventArgs e, TextBox textbox, double tailleMini, double tailleMaxi, string carNonAutorisé)
    {            
        //Recherche dans la TextBox, la première occurrence de l'expression régulière.
        Match match = Regex.Match(textbox.Text, carNonAutorisé);
        /*Si il y a une Mauvaise occurence:
         *   - On efface le contenu collé
         *   - On prévient l'utilisateur 
         */
        if (match.Success)
        {
            textbox.Text = "";
            MessageBox.Show("Votre copie un ou des caractère(s) non autorisé", "Attention", MessageBoxButtons.OK, MessageBoxIcon.Information);
        }
        tailleTextBox(textbox, tailleMini, tailleMaxi);
    }

在另一个类我用这个静态梅索德像这样

In another class i use this static methode like this

    private void tbxSigné_TextChanged(object sender, EventArgs e)
    {
        FiltreTbx.textChanged(e, tbxSigné, double.MinValue, double.MaxValue, @"[^\d\,\;\.\-]");
    }

我wan't做的是这样的事情：

What i wan't to do is something like that:

  if (match.Success)
    {
        textbox.Text = //Write the text before users paste in the textbox;

    }

任何人都有一个想法吗？

Anyone have an idea please?

推荐答案

首先，你有没有考虑过使用的 MaskedTextBox中呢？它可以处理的字符过滤你。

First of all, have you considered using MaskedTextBox instead? It can handle the character filtering for you.

不过，为了这个练习中，你能想到沿着这条线的解决方案中。这是用法：

However, for the sake of this exercise, you could think of a solution along this line. This is the usage:

public Form1()
{
    InitializeComponent();

    FiltreTbx.AddTextBoxFilter(tbxSigné,
                               double.MinValue, double.MaxValue,
                               @"[^\d\,\;\.\-]");
}

本 AddTextBoxFilter 是一个新的静态方法，你只能叫一次。这将增加一个框TextChanged处理程序的文本框。该处理器采用的是关闭存储previous 正文在文本框中。

This AddTextBoxFilter is a new static method, which you only call once. It will add a TextChanged handler to the TextBox. This handler uses a closure to store the previous Text in the text box.

您的静态方法获得一个额外的参数来传递沿着这条previous文本。

Your static method gained an extra parameter to pass along this previous text.

public class FiltreTbx
{
    public static void AddTextBoxFilter(TextBox textbox,
                                        double tailleMini, double tailleMaxi,
                                        string carNonAutorisé)
    {
        string previousText = textbox.Text;

        textbox.TextChanged +=
            delegate(object sender, EventArgs e)
            {
                 textChanged(e, textbox, tailleMini, tailleMaxi,
                             carNonAutorisé, previousText);
                 previousText = textbox.Text;
            };
    }

    static public void textChanged(EventArgs e, TextBox textbox,
                                   double tailleMini, double tailleMaxi,
                                   string carNonAutorisé, string previousText)
    {
        //Recherche dans la TextBox, la première occurrence de l'expression régulière.
        Match match = Regex.Match(textbox.Text, carNonAutorisé);
        /*Si il y a une Mauvaise occurence:
         *   - On efface le contenu collé
         *   - On prévient l'utilisateur 
         */
        if (match.Success)
        {
            // Set the Text back to the value it had after the previous
            // TextChanged event.
            textbox.Text = previousText;
            MessageBox.Show("Votre copie un ou des caractère(s) non autorisé",
                            "Attention", MessageBoxButtons.OK,
                            MessageBoxIcon.Information);
        }
        tailleTextBox(textbox, tailleMini, tailleMaxi);
    }
}

我不知道是什么 tailleTextBox 是应该做的正好，你不包括源$ C ​​$ C，但我怀疑它强制的最小值和最大值？

I'm not sure what tailleTextBox is supposed to do exactly, you did not include that source code, but I suspect it enforces the minimum and maximum values?

。这样做的一种方式是将通过创建一个专门控制：

If you want to handle the Paste operation yourself, before it even happens, you will have to intercept the WM_PASTE message to the text box. One way of doing is would be by creating a specialized control:

using System;
using System.Windows.Forms;

class MyTextBox : TextBox
{
    private const int WM_PASTE = 0x0302;

    protected override void WndProc(ref Message m)
    {
        if (m.Msg != WM_PASTE)
        {
            // Handle all other messages normally
            base.WndProc(ref m);
        }
        else
        {
            // Some simplified example code that complete replaces the
            // text box content only if the clipboard contains a valid double.
            // I'll leave improvement of this behavior as an exercise :)
            double value;
            if (double.TryParse(Clipboard.GetText(), out value))
            {
                Text = value.ToString();
            }
        }
    }
}

如果你定义的类在你的WinForms项目，你应该能够将其拖动到你的表单像任何其他的控制。

If you define the class in your WinForms project, you should be able to drag it onto your form like any other control.

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