ValidateTextBox（只能输入数字文本框）

这里我们创建2个TextBox 控件，应用WinForm的验证机制使得TextBox 只能输入数字否则提示错误并且不允许鼠标焦点切换 。

ValidateForm.Designer.cs代码如下：

namespace validateTextForm
...{
    partial class ValidateForm
    ...{
        /**//// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /**//// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing)
        ...{
            if (disposing && (components != null))
            ...{
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        Windows Form Designer generated code#region Windows Form Designer generated code

        /**//// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        ...{
            this.components = new System.ComponentModel.Container();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.groupBox1 = new System.Windows.Forms.GroupBox();
            this.textBox2 = new System.Windows.Forms.TextBox();
            this.errorProvider1 = new System.Windows.Forms.ErrorProvider(this.components);
            this.errorProvider2 = new System.Windows.Forms.ErrorProvider(this.components);
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.groupBox1.SuspendLayout();
            ((System.ComponentModel.ISupportInitialize)(this.errorProvider1)).BeginInit();
            ((System.ComponentModel.ISupportInitialize)(this.errorProvider2)).BeginInit();
            this.SuspendLayout();
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(30, 21);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(75, 22);
            this.textBox1.TabIndex = 0;
            this.textBox1.Validating += new System.ComponentModel.CancelEventHandler(this.textBox1_Validating);
            // 
            // groupBox1
            // 
            this.groupBox1.Controls.Add(this.button2);
            this.groupBox1.Controls.Add(this.button1);
            this.groupBox1.Controls.Add(this.textBox2);
            this.groupBox1.Controls.Add(this.textBox1);
            this.groupBox1.Font = new System.Drawing.Font("Verdana", 9F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
            this.groupBox1.Location = new System.Drawing.Point(23, 12);
            this.groupBox1.Name = "groupBox1";
            this.groupBox1.Size = new System.Drawing.Size(243, 97);
            this.groupBox1.TabIndex = 1;
            this.groupBox1.TabStop = false;
            this.groupBox1.Text = "Validate";
            // 
            // textBox2
            // 
            this.textBox2.Location = new System.Drawing.Point(140, 21);
            this.textBox2.Name = "textBox2";
            this.textBox2.Size = new System.Drawing.Size(75, 22);
            this.textBox2.TabIndex = 1;
            this.textBox2.Validating += new System.ComponentModel.CancelEventHandler(this.textBox2_Validating);
            // 
            // errorProvider1
            // 
            this.errorProvider1.ContainerControl = this;
            // 
            // errorProvider2
            // 
            this.errorProvider2.ContainerControl = this;
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(30, 61);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(75, 23);
            this.button1.TabIndex = 2;
            this.button1.Text = "Validate";
            this.button1.UseVisualStyleBackColor = true;
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // button2
            // 
            this.button2.Location = new System.Drawing.Point(140, 61);
            this.button2.Name = "button2";
            this.button2.Size = new System.Drawing.Size(75, 23);
            this.button2.TabIndex = 3;
            this.button2.Text = "Reset";
            this.button2.UseVisualStyleBackColor = true;
            this.button2.Click += new System.EventHandler(this.button2_Click);
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(288, 131);
            this.Controls.Add(this.groupBox1);
            this.Name = "Form1";
            this.Text = "Validating";
            this.FormClosing += new System.Windows.Forms.FormClosingEventHandler(this.Form1_FormClosing);
            this.groupBox1.ResumeLayout(false);
            this.groupBox1.PerformLayout();
            ((System.ComponentModel.ISupportInitialize)(this.errorProvider1)).EndInit();
            ((System.ComponentModel.ISupportInitialize)(this.errorProvider2)).EndInit();
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.GroupBox groupBox1;
        private System.Windows.Forms.TextBox textBox2;
        private System.Windows.Forms.ErrorProvider errorProvider1;
        private System.Windows.Forms.ErrorProvider errorProvider2;
        private System.Boolean Flag = false;
        private System.Windows.Forms.Button button2;
        private System.Windows.Forms.Button button1;
    }
}

ValidateForm.cs代码如下：

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

namespace validateTextForm
...{
    public partial class ValidateForm : Form
    ...{
        public ValidateForm()
        ...{
            InitializeComponent();
        }

        private void textBox1_Validating(object sender, CancelEventArgs e)
        ...{
            Int32 intValue;
            if (!Int32.TryParse(textBox1.Text, out intValue))
            ...{
                errorProvider1.SetError(textBox1, "must be integer !");
                Flag = true;
                e.Cancel = true;
            }
            else
            ...{
                errorProvider1.SetError(textBox1,null);   
            }
        }

        private void textBox2_Validating(object sender, CancelEventArgs e)
        ...{
            Int32 intValue;
            if (!Int32.TryParse(textBox2.Text, out intValue))
            ...{
                errorProvider2.SetError(textBox2, "must be integer !");
                Flag = true;
                e.Cancel = true;
            }
            else
            ...{
                errorProvider2.SetError(textBox2, null);
            }
        }

        private void Form1_FormClosing(object sender, FormClosingEventArgs e)
        ...{
              if (Flag == true)
            ...{
                e.Cancel = false;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        ...{
            MessageBox.Show("Validating Successful !");
        }

        private void button2_Click(object sender, EventArgs e)
        ...{
            textBox1.Text = textBox2.Text = String.Empty;
        }
    }
}