使用键盘输入只能录入数字和点代码

使用键盘输入只能录入数字和点代码 using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Text.RegularExpressions; namespace Subject { public partial class CountForm : Form { public CountForm() { InitializeComponent(); } private void btnExit_Click(object sender, EventArgs e) { Application.Exit(); } private void cboCount_SelectedIndexChanged(object sender, EventArgs e) { } private void btnCount_Click(object sender, EventArgs e) { //如果按下计算运算符为空则提示 if (cboCount.Text.Trim()=="") { MessageBox.Show("请选择运算符", "提示", MessageBoxButtons.OK); } //定义变量并且类型转换为double类型 double countone = double.Parse(txtFirst.Text.Trim()); double counttwo = double.Parse(txtSecond.Text.Trim()); double countthree = 0; //使用分支语句进行选择计算条件 switch (cboCount.Text.Trim()) { case "+": countthree = countone + counttwo; txtThree.Text = countthree.ToString(); break; case "-": countthree = countone - counttwo; txtThree.Text = countthree.ToString(); break; case "*": countthree = countone * counttwo; txtThree.Text = countthree.ToString(); break; case "/": countthree = countone / counttwo; txtThree.Text = countthree.ToString(); break; } } private void txtFirst_TextChanged(object sender, EventArgs e) { } //定义变量寻找点数量 int index = 0; //使用时间KeyPress private void txtFirst_KeyPress(object sender, KeyPressEventArgs e) { //先阻止从键盘输入键 e.Handled = true; //键盘只能录入的键有数字、backsp、"."、 if (e.KeyChar >= 48 && e.KeyChar <= 57 || e.KeyChar == 8 || e.KeyChar == 46) { //输入的字符中不存在点 if (this.txtFirst.Text.IndexOf(".")==-1) { //点的个数为0 index = 0; } //当键盘录入点的时候 if (e.KeyChar == 46) { //点的个数加1 index++; //没有录入字符 if (this.txtFirst.Text.Length <= 0) { //阻止键盘录入 e.Handled = true; } //当录入的“.”个数大于1个的时候阻止键盘录入 else if (index>1) { e.Handled = true; } //除了以上两个条件其它都成立 else { //可以键盘录入 e.Handled = false; } } //键盘录入的不是“.”时候可以录入 else { e.Handled = false; } } } private void txtSecond_KeyPress(object sender, KeyPressEventArgs e) { //先阻止从键盘输入键 e.Handled = true; //键盘只能录入的键有数字、backsp、"."、 if (e.KeyChar >= 48 && e.KeyChar <= 57 || e.KeyChar == 8 || e.KeyChar == 46) { //输入的字符中不存在点 if (this.txtSecond.Text.IndexOf(".") == -1) { //点的个数为0 index = 0; } //当键盘录入点的时候 if (e.KeyChar == 46) { //点的个数加1 index++; //没有录入字符首位是“.”的时候 if (this.txtSecond.Text.Length <= 0) { //阻止键盘录入 e.Handled = true; } //当录入的“.”个数大于1个的时候阻止键盘录入 else if (index > 1) { e.Handled = true; } //除了以上两个条件其它都成立 else { //可以键盘录入 e.Handled = false; } } //键盘录入的不是“.”时候可以录入 else { e.Handled = false; } } } } }