如何让TextBox只能输入数字、汉字、字母？

在编程的过程中我们可能经常会用到TextBox只接受数字输入（或者其他，比如：汉字，字母，等等），这个时候我们可能需要重新封装一个
TextBox（其他方法当然也可以），经常看到有人问这个问题，今天抽了一点时间将此封装做了一下，现在共享大家，希望能给大家带来一定的帮助，如有不
妥敬请斧正，另外：如需转载请注明出处：

alimama_pid="mm_10249644_1605763_5018464";
alimama_type="f";
alimama_sizecode ="tl_1x1_8";
alimama_fontsize=12;
alimama_bordercolor="FFFFFF";
alimama_bgcolor="FFFFFF";
alimama_titlecolor="0000FF";
alimama_underline=0;
alimama_height=22;
alimama_width=0;



只能输入数字（int型）的代码（直接复制就ＯＫ了）

public class IntTextBox : System.Windows.Forms.TextBox
{
private int selectPos = 0;
public IntTextBox()
: base()
{
this.BackColor = Color.Beige;
this.TextChanged += new EventHandler(this.TextChage);
this.Leave += new EventHandler(this.FocusLeave);
}
//焦点发生改变时，此处你可以根据自己需要自己选择
public void FocusLeave(object sender, System.EventArgs e)
{
if (this.Text != "")
{
this.Text = ToDBC(this.Text);
if (!(new Regex(@"^-?/d+$")).IsMatch(this.Text))
{
this.BackColor = Color.OrangeRed;
MessageBox.Show("输入内容不合法！", "输入提示");
this.Focus();
}
else
{
this.BackColor = Color.Beige;
}
}
}

//内容发生改变时
public void TextChage(object sender, System.EventArgs e)
{
selectPos = this.SelectionStart;
if (this.Text != "")
{
//此处采用郑州表达式

alimama_pid="mm_10249644_1605763_4930558";
alimama_type="f";
alimama_sizecode ="tl_1x5_8";
alimama_fontsize=12;
alimama_bordercolor="FFFFFF";
alimama_bgcolor="FFFFFF";
alimama_titlecolor="0000FF";
alimama_underline=0;
alimama_height=22;
alimama_width=512;



if (!(new Regex(@"^-?/d+$")).IsMatch(this.Text))
{
this.BackColor = Color.OrangeRed;
this.SelectionStart = selectPos;
}
else
{
this.BackColor = Color.Beige;
this.SelectionStart = selectPos;
}
}
else
{
this.BackColor = Color.Beige;
}
}

//全角转换成半角，此功能也可以选择
public string ToDBC(string input)
{
char[] c = input.ToCharArray();
for (int i = 0; i < c.Length; i++)
{
if (c[i] == 12288)
{
c[i] = (char)32;
continue;
}
if (c[i] > 65280 && c[i] < 65375)
c[i] = (char)(c[i] - 65248);
}
return new string(c);
}
}

下面代码是只能输入浮点数（至于其他的比如汉字、字母等等原理一样）

alimama_pid="mm_10249644_1605763_4930558";
alimama_type="f";
alimama_sizecode ="tl_1x5_8";
alimama_fontsize=12;
alimama_bordercolor="FFFFFF";
alimama_bgcolor="FFFFFF";
alimama_titlecolor="0000FF";
alimama_underline=0;
alimama_height=22;
alimama_width=512;

public class FloatTextBox : System.Windows.Forms.TextBox
{
private int selectPos = 0;
public FloatTextBox()
: base()
{
this.BackColor = Color.Beige;
this.TextChanged += new EventHandler(this.TextChage);
this.Leave += new EventHandler(this.FocusLeave);
}
//焦点发生改变时
public void FocusLeave(object sender, System.EventArgs e)
{
if (this.Text != "")
{
this.Text = ToDBC(this.Text);
if (!(new Regex(@"^/d+(/./d+)?$")).IsMatch(this.Text))
{
this.BackColor = Color.OrangeRed;
MessageBox.Show("输入内容不合法！", "输入提示");
this.Focus();
}
else
{
this.BackColor = Color.Beige;
}
}
}

//内容发生改变时
public void TextChage(object sender, System.EventArgs e)
{
selectPos = this.SelectionStart;
if (this.Text != "")
{
if (!(new Regex(@"^/d+(/./d+)?$")).IsMatch(this.Text))
{
this.BackColor = Color.OrangeRed;
this.SelectionStart = selectPos;
}
else
{
this.BackColor = Color.Beige;
this.SelectionStart = selectPos;
}
}
else
{
this.BackColor = Color.Beige;
}
}

//全角转换成半角
public string ToDBC(string input)
{
char[] c = input.ToCharArray();
for (int i = 0; i < c.Length; i++)
{
if (c[i] == 12288)
{
c[i] = (char)32;
continue;
}
if (c[i] > 65280 && c[i] < 65375)
c[i] = (char)(c[i] - 65248);
}
return new string(c);
}
}