有没有办法在 c# winform 的文本框中一键选择所有内容？

Question

我正在制作一个猜数字游戏，为了方便起见，我想在我的程序中添加一行代码，只需单击一下即可选择文本框中的所有文本。我已经尝试了在这里找到的所有内容以及我在谷歌上找到的其他故障排除网站，但似乎都不起作用，甚至试图强制将焦点放在文本框上。文本框的行为仍然像普通文本框一样，即必须双击才能选择全部。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace randomNumberGuessingGameFourthTry
{
     public partial class Form1 : Form
     {
         public Form1()
         {
          InitializeComponent();
         }

    private void startGame_Click(object sender, EventArgs e)
    {
        if (min.Text == "" || min.Text == " " || min.Text == "Min")
        {
            MessageBox.Show("You didn't enter a minimum value of zero or greater so the default value of 0 was set.");
            min.Text = "0";
        }

        if (max.Text == "" || max.Text == " " || max.Text == "Max")
        {
            MessageBox.Show("You didn't enter a maximum value so the default value of 10 was set.");
            max.Text = "11";
        }

        startGuessing startGame = new startGuessing(min.Text, max.Text);
        this.Hide();
        startGame.ShowDialog();
    }

   private void exitGame_Click(object sender, EventArgs e)
    {
        Application.Exit();
    }

    private void min_TextChanged(object sender, EventArgs e)
    {
        min.Focus();
        min.SelectAll();
        min.SelectionLength = min.Text.Length;

        int userInput1 = Convert.ToInt32(min.Text);
        if (!(userInput1 >= 0))
        {
            MessageBox.Show("Your min range must be at least 0 or higher", "Invalid range found");
        }
    }

    private void max_TextChanged(object sender, EventArgs e)
    {


        int userInput1 = Convert.ToInt32(min.Text);
        int userInput2 = Convert.ToInt32(max.Text);
        if (!(userInput2 <= userInput1 + 9))
        {
            MessageBox.Show("Your max range must be at least 10 digits higher than " + userInput1, "Invalid range found");
        }
    }
}

}

上面是我的 form1.cs 的代码，我想如果我能让它在这里工作，我就可以让它在这个程序中的第二个表单上工作。

Answer 1

您应该首先调用SelectAll()方法 then Focus()，而不是相反。这个最小的例子对我有用：

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        textBox1.Click += TextBoxOnClick;
    }

    private void TextBoxOnClick(object sender, EventArgs eventArgs)
    {
        var textBox = (TextBox) sender;
        textBox.SelectAll();
        textBox.Focus();
    }
}