本文实例讲述了C#中设置textbox限制条件的方法，分享给大家供大家参考。具体实现方法如下：

#region 设置数量等textbox控件样式及限制条件（具体调用的方法就是重写或直接调用ShieldNumberTextBoxOtherKeys函数）

/// <summary>

/// 屏蔽数字textbox的其他字符串

/// </summary>

/// <param name="sender"></param>

/// <param name="e"></param>

public virtual void tBoxNumbers_KeyDown(object sender, KeyEventArgs e)

{

    e.SuppressKeyPress = true;
    switch (e.KeyCode)

    {

 case Keys.D0:

 case Keys.D1:

 case Keys.D2:

 case Keys.D3:

 case Keys.D4:

 case Keys.D5:

 case Keys.D6:

 case Keys.D7:

 case Keys.D8:

 case Keys.D9:

 case Keys.NumPad0:

 case Keys.NumPad1:

 case Keys.NumPad2:

 case Keys.NumPad3:

 case Keys.NumPad4:

 case Keys.NumPad5:

 case Keys.NumPad6:

 case Keys.NumPad7:

 case Keys.NumPad8:

 case Keys.NumPad9:

 case Keys.Back:

 case Keys.OemPeriod:

 case Keys.Delete:

 case Keys.Decimal:

     e.SuppressKeyPress = false;

     break;

 default:

     break;

    }

}
public virtual void tBoxNumbers_KeyPress(object sender, KeyPressEventArgs e)

{

    TextBox tBox = sender as TextBox;

    char c = e.KeyChar;
    if (c.ToString().Equals("."))

    {

 if (tBox.Text.Length <= 0)

     e.Handled = true;           //小数点不能在第一位     

 else

 {

     float f;

     float oldf;

     bool b1 = false, b2 = false;

     b1 = float.TryParse(tBox.Text, out oldf);

     b2 = float.TryParse(tBox.Text + e.KeyChar.ToString(), out f);

     if (b2 == false)

     {

  if (b1 == true)

      e.Handled = true;

  else

      e.Handled = false;

     }

 }

    }

}
/// <summary>

/// 屏蔽数字textbox的其他字符串

/// </summary>

/// <param name="tbox">要屏蔽的textbox</param>

public virtual void ShieldNumberTextBoxOtherKeys(TextBox tbox)

{

    tbox.ImeMode = ImeMode.Disable;

    tbox.KeyDown += tBoxNumbers_KeyDown;

    tbox.KeyPress += tBoxNumbers_KeyPress;

}
#endregion

希望本文所述对大家的C#程序设计有所帮助。