namespace csharptest
{partial class Form1{/// <summary>/// 必需的设计器变量。/// </summary>private System.ComponentModel.IContainer components = null;/// <summary>/// 清理所有正在使用的资源。/// </summary>/// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>protected override void Dispose(bool disposing){if (disposing && (components != null)){components.Dispose();}base.Dispose(disposing);}#region Windows 窗体设计器生成的代码/// <summary>/// 设计器支持所需的方法 - 不要/// 使用代码编辑器修改此方法的内容。/// </summary>private void InitializeComponent(){this.textBox1 = new System.Windows.Forms.TextBox();this.label1 = new System.Windows.Forms.Label();this.button1 = new System.Windows.Forms.Button();this.SuspendLayout();// // textBox1// this.textBox1.Location = new System.Drawing.Point(24, 49);this.textBox1.Name = "textBox1";this.textBox1.Size = new System.Drawing.Size(185, 21);this.textBox1.TabIndex = 0;// // label1// this.label1.AutoSize = true;this.label1.Location = new System.Drawing.Point(51, 19);this.label1.Name = "label1";this.label1.Size = new System.Drawing.Size(131, 12);this.label1.TabIndex = 1;this.label1.Text = "请输入0~6个字母或数字";// // button1// this.button1.Location = new System.Drawing.Point(72, 85);this.button1.Name = "button1";this.button1.Size = new System.Drawing.Size(75, 23);this.button1.TabIndex = 2;this.button1.Text = "确认";this.button1.UseVisualStyleBackColor = true;this.button1.Click += new System.EventHandler(this.button1_Click);// // Form1// this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 12F);this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;this.ClientSize = new System.Drawing.Size(227, 124);this.Controls.Add(this.button1);this.Controls.Add(this.label1);this.Controls.Add(this.textBox1);this.Name = "Form1";this.Text = "EditBox";this.ResumeLayout(false);this.PerformLayout();}#endregionprivate System.Windows.Forms.TextBox textBox1;private System.Windows.Forms.Label label1;private System.Windows.Forms.Button button1;}
}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;namespace csharptest
{public partial class Form1 : Form{public Form1(){InitializeComponent();}private bool check(String text){if (text.Length <= 0) return false;if (text.Length > 6) return false;for (int i = 0; i < text.Length; i++){char c = text[i];if ((c < 'a' || c > 'z') && (c < 'A' || c > 'Z') && (c < '0' || c > '9'))return false;}return true;}private void button1_Click(object sender, EventArgs e){if (check(textBox1.Text))MessageBox.Show("Accepted");elseMessageBox.Show("Please try again.");}}
}