似乎目前对这个问题的许多答案都是手动解析输入文本。如果你正在寻找一个特定的内置数字类型(例如int或double)，为什么不只是将工作委托给该类型的TryParse方法?例如:

public class IntTextBox : TextBox
{
    string PreviousText = "";
    int BackingResult;

    public IntTextBox()
    {
        TextChanged += IntTextBox_TextChanged;
    }

    public bool HasResult { get; private set; }

    public int Result
    {
        get
        {
            return HasResult ? BackingResult : default(int);
        }
    }

    void IntTextBox_TextChanged(object sender, EventArgs e)
    {
        HasResult = int.TryParse(Text, out BackingResult);

        if (HasResult || string.IsNullOrEmpty(Text))
        {
            // Commit
            PreviousText = Text;
        }
        else
        {
            // Revert
            var changeOffset = Text.Length - PreviousText.Length;
            var previousSelectionStart =
                Math.Max(0, SelectionStart - changeOffset);

            Text = PreviousText;
            SelectionStart = previousSelectionStart;
        }
    }
}

如果你想要更通用但仍然兼容Visual Studio的设计器:

public class ParsableTextBox : TextBox
{
    TryParser BackingTryParse;
    string PreviousText = "";
    object BackingResult;

    public ParsableTextBox()
        : this(null)
    {
    }

    public ParsableTextBox(TryParser tryParse)
    {
        TryParse = tryParse;

        TextChanged += ParsableTextBox_TextChanged;
    }

    public delegate bool TryParser(string text, out object result);

    public TryParser TryParse
    {
        set
        {
            Enabled = !(ReadOnly = value == null);

            BackingTryParse = value;
        }
    }

    public bool HasResult { get; private set; }

    public object Result
    {
        get
        {
            return GetResult<object>();
        }
    }

    public T GetResult<T>()
    {
        return HasResult ? (T)BackingResult : default(T);
    }

    void ParsableTextBox_TextChanged(object sender, EventArgs e)
    {
        if (BackingTryParse != null)
        {
            HasResult = BackingTryParse(Text, out BackingResult);
        }

        if (HasResult || string.IsNullOrEmpty(Text))
        {
            // Commit
            PreviousText = Text;
        }
        else
        {
            // Revert
            var changeOffset = Text.Length - PreviousText.Length;
            var previousSelectionStart =
                Math.Max(0, SelectionStart - changeOffset);

            Text = PreviousText;
            SelectionStart = previousSelectionStart;
        }
    }
}

最后，如果你想要完全通用的东西，不关心Designer支持:

public class ParsableTextBox<T> : TextBox
{
    TryParser BackingTryParse;
    string PreviousText;
    T BackingResult;

    public ParsableTextBox()
        : this(null)
    {
    }

    public ParsableTextBox(TryParser tryParse)
    {
        TryParse = tryParse;

        TextChanged += ParsableTextBox_TextChanged;
    }

    public delegate bool TryParser(string text, out T result);

    public TryParser TryParse
    {
        set
        {
            Enabled = !(ReadOnly = value == null);

            BackingTryParse = value;
        }
    }

    public bool HasResult { get; private set; }

    public T Result
    {
        get
        {
            return HasResult ? BackingResult : default(T);
        }
    }

    void ParsableTextBox_TextChanged(object sender, EventArgs e)
    {
        if (BackingTryParse != null)
        {
            HasResult = BackingTryParse(Text, out BackingResult);
        }

        if (HasResult || string.IsNullOrEmpty(Text))
        {
            // Commit
            PreviousText = Text;
        }
        else
        {
            // Revert
            var changeOffset = Text.Length - PreviousText.Length;
            var previousSelectionStart =
                Math.Max(0, SelectionStart - changeOffset);

            Text = PreviousText;
            SelectionStart = previousSelectionStart;
        }
    }
}

故障安全和简单的“递归”方法，可用于多个文本框。

它可以阻止错误的键盘输入字符，也可以粘贴值等。它只接受整数，最大数字长度是字符串类型的最大长度(它是int，真的很长!)

public void Check_If_Int_On_TextChanged(object sender, EventArgs e)
{
   // This method checks that each inputed character is a number. Any non-numeric
   // characters are removed from the text

   TextBox textbox = (TextBox)sender;

   // If the text is empty, return
   if (textbox.Text.Length == 0) { return; }

   // Check the new Text value if it's only numbers
   byte parsedValue;
   if (!byte.TryParse(textbox.Text[(textbox.Text.Length - 1)].ToString(), out parsedValue))
   {
      // Remove the last character as it wasn't a number
      textbox.Text = textbox.Text.Remove((textbox.Text.Length - 1));

      // Move the cursor to the end of text
      textbox.SelectionStart = textbox.Text.Length;
    }
 }

只是因为在一条线上做事情总是更有趣……

 private void textBox1_KeyPress(object sender, KeyPressEventArgs e)
    {
        e.Handled = !char.IsDigit(e.KeyChar) && !char.IsControl(e.KeyChar);
    }

注意:这并不阻止用户复制/粘贴到此文本框。这并不是清除数据的安全方法。

Here is a simple solution that works for me.

public static bool numResult;
    public static bool checkTextisNumber(string numberVal)
    {
        try
        {
            if (numberVal.Equals("."))
            {
                numResult = true;
            }
            else if (numberVal.Equals(""))
            {
                numResult = true;
            }
            else
            {
                decimal number3 = 0;
                bool canConvert = decimal.TryParse(numberVal, out number3);
                if (canConvert == true)
                {
                    numResult = true;
                }
                else
                    numResult = false;
            }

        }
        catch (System.Exception ex)
        {
            numResult = false;
        }
        return numResult;
    }
    string correctNum;
    private void tBox_NumTester_TextChanged(object sender, TextChangedEventArgs e)
    {


        if(checkTextisNumber(tBox_NumTester.Text))
        {
            correctNum = tBox_NumTester.Text;
        }
        else
        {
            tBox_NumTester.Text = correctNum;
        }

    }

我从上下文和您使用的标记假设您正在编写一个。net c#应用程序。在这种情况下，您可以订阅文本更改事件，并验证每个按键。

private void textBox1_TextChanged(object sender, EventArgs e)
{
    if (System.Text.RegularExpressions.Regex.IsMatch(textBox1.Text, "[^0-9]"))
    {
        MessageBox.Show("Please enter only numbers.");
        textBox1.Text = textBox1.Text.Remove(textBox1.Text.Length - 1);
    }
}

看一下WinForm中的输入处理

我已经发布了我的解决方案，在文本框上使用ProcessCmdKey和OnKeyPress事件。注释向您展示了如何使用Regex来验证键按和适当地阻止/允许。