使用Visual Studio写一个简单的Windows窗体应用登录界面

需要的知识：C#的基本语法，以及Visual Studio的基本操作方法

编辑软件：Sql Server 2017，Visual Studio 2017

前提：Sql Server 中有一个名为"MY-LAPTOP"的服务器，一个名为"Test"的数据库，库下有一个名为"Login_Table"的表

一、编写Form1，登录主界面

首先编写Form1.Designer.cs

namespace WindowsFormsApp3{    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 - 不要修改        /// 使用代码编辑器修改此方法的内容。        /// </summary>        private void InitializeComponent()        {            this.label1 = new System.Windows.Forms.Label();            this.label2 = new System.Windows.Forms.Label();            this.button1 = new System.Windows.Forms.Button();            this.button2 = new System.Windows.Forms.Button();            this.button3 = new System.Windows.Forms.Button();            this.textBox1 = new System.Windows.Forms.TextBox();            this.textBox2 = new System.Windows.Forms.TextBox();            this.label3 = new System.Windows.Forms.Label();            this.linkLabel1 = new System.Windows.Forms.LinkLabel();            this.checkBox1 = new System.Windows.Forms.CheckBox();            this.SuspendLayout();            //             // label1            //             this.label1.AutoSize = true;            this.label1.Enabled = false;            this.label1.Font = new System.Drawing.Font("宋体", 15F);            this.label1.ForeColor = System.Drawing.SystemColors.ControlText;            this.label1.Location = new System.Drawing.Point(49, 41);            this.label1.Name = "label1";            this.label1.Size = new System.Drawing.Size(87, 25);            this.label1.TabIndex = 0;            this.label1.Text = "账号：";            this.label1.Click += new System.EventHandler(this.label1_Click);            //             // label2            //             this.label2.AutoSize = true;            this.label2.Enabled = false;            this.label2.Font = new System.Drawing.Font("宋体", 15F);            this.label2.ForeColor = System.Drawing.SystemColors.ControlText;            this.label2.Location = new System.Drawing.Point(49, 98);            this.label2.Name = "label2";            this.label2.Size = new System.Drawing.Size(87, 25);            this.label2.TabIndex = 1;            this.label2.Text = "密码：";            this.label2.Click += new System.EventHandler(this.label2_Click);            //             // button1            //             this.button1.Font = new System.Drawing.Font("宋体", 13F);            this.button1.Location = new System.Drawing.Point(54, 168);            this.button1.Name = "button1";            this.button1.Size = new System.Drawing.Size(82, 33);            this.button1.TabIndex = 2;            this.button1.Text = "登录";            this.button1.UseVisualStyleBackColor = true;            this.button1.Click += new System.EventHandler(this.button1_Click);            //             // button2            //             this.button2.Font = new System.Drawing.Font("宋体", 13F);            this.button2.Location = new System.Drawing.Point(190, 168);            this.button2.Name = "button2";            this.button2.Size = new System.Drawing.Size(90, 33);            this.button2.TabIndex = 3;            this.button2.Text = "注册";            this.button2.UseVisualStyleBackColor = true;            this.button2.Click += new System.EventHandler(this.button2_Click);            //             // button3            //             this.button3.Font = new System.Drawing.Font("宋体", 13F);            this.button3.Location = new System.Drawing.Point(329, 168);            this.button3.Name = "button3";            this.button3.Size = new System.Drawing.Size(79, 33);            this.button3.TabIndex = 4;            this.button3.Text = "取消";            this.button3.UseVisualStyleBackColor = true;            this.button3.Click += new System.EventHandler(this.button3_Click);            //             // textBox1            //             this.textBox1.Font = new System.Drawing.Font("宋体", 14F);            this.textBox1.Location = new System.Drawing.Point(134, 38);            this.textBox1.Name = "textBox1";            this.textBox1.Size = new System.Drawing.Size(274, 34);            this.textBox1.TabIndex = 5;            //             // textBox2            //             this.textBox2.Font = new System.Drawing.Font("宋体", 14F);            this.textBox2.Location = new System.Drawing.Point(134, 96);            this.textBox2.Name = "textBox2";            this.textBox2.PasswordChar = '*';            this.textBox2.Size = new System.Drawing.Size(274, 34);            this.textBox2.TabIndex = 6;            //             // label3            //             this.label3.AutoSize = true;            this.label3.Location = new System.Drawing.Point(54, 217);            this.label3.Name = "label3";            this.label3.Size = new System.Drawing.Size(0, 15);            this.label3.TabIndex = 7;            //             // linkLabel1            //             this.linkLabel1.AutoSize = true;            this.linkLabel1.Location = new System.Drawing.Point(321, 134);            this.linkLabel1.Name = "linkLabel1";            this.linkLabel1.Size = new System.Drawing.Size(83, 15);            this.linkLabel1.TabIndex = 8;            this.linkLabel1.TabStop = true;            this.linkLabel1.Text = "忘记密码>>";            //             // checkBox1            //             this.checkBox1.AutoSize = true;            this.checkBox1.Location = new System.Drawing.Point(415, 110);            this.checkBox1.Name = "checkBox1";            this.checkBox1.Size = new System.Drawing.Size(89, 19);            this.checkBox1.TabIndex = 9;            this.checkBox1.Text = "显示密码";            this.checkBox1.UseVisualStyleBackColor = true;            this.checkBox1.CheckedChanged += new System.EventHandler(this.checkBox1_CheckedChanged);            //             // Form1            //             this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 15F);            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;            this.ClientSize = new System.Drawing.Size(508, 244);            this.Controls.Add(this.checkBox1);            this.Controls.Add(this.linkLabel1);            this.Controls.Add(this.label3);            this.Controls.Add(this.textBox2);            this.Controls.Add(this.textBox1);            this.Controls.Add(this.button3);            this.Controls.Add(this.button2);            this.Controls.Add(this.button1);            this.Controls.Add(this.label2);            this.Controls.Add(this.label1);            this.Name = "Form1";            this.Text = "Form1";            this.Load += new System.EventHandler(this.Form1_Load);            this.ResumeLayout(false);            this.PerformLayout();        }        #endregion        private System.Windows.Forms.Label label1;        private System.Windows.Forms.Label label2;        private System.Windows.Forms.Button button1;        private System.Windows.Forms.Button button2;        private System.Windows.Forms.Button button3;        private System.Windows.Forms.TextBox textBox1;        private System.Windows.Forms.TextBox textBox2;        private System.Windows.Forms.Label label3;        private System.Windows.Forms.LinkLabel linkLabel1;        private System.Windows.Forms.CheckBox checkBox1;    }}

以下代码中编写了SqlHelp类，其作用是封装连接数据库语句，这样就可以不用每次都编写连接数据库语句，如此便可快速完成编写

如果对SqlHelp类不理解可以参考：http://blog.csdn.net/yinnan0422/article/details/51691096

如果对SqlCommand用法不理解可以参考：http://blog.csdn.net/jintougao/article/details/8587661

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;using System.Data.Sql;using System.Data.SqlClient;using System.Windows.Forms;namespace WindowsFormsApp3{    class SqlHelp    {        /// <summary>        /// DataSource : MY-LAPTOP        /// Initial Catalog: Test        /// User ID:        /// Password:        /// </summary>                private const string connectionString = @"Data Source=MY-LAPTOP;Initial Catalog=Test;Integrated Security = SSPI";                public SqlHelp() { }        public static SqlConnection conn;        //打开数据库连接        public static void OpenConn()        {            string SqlCon = connectionString;//数据库连接字符串            conn = new SqlConnection(SqlCon);            if (conn.State==ConnectionState.Closed)            {                conn.Open();            }        }        //关闭数据库连接        public static void CloseConn() {            if(conn.State.ToString().ToLower() == "open")            {                conn.Close();                conn.Dispose();            }        }        //读取数据        public static SqlDataReader GetDataReaderValue(string sql) {            OpenConn();            SqlCommand cmd = new SqlCommand(sql,conn);            SqlDataReader dr = cmd.ExecuteReader();            CloseConn();            return dr;        }        //返回DataSet        public static DataSet GetDataSetValue(string sql, string tableName) {            OpenConn();            SqlDataAdapter da = new SqlDataAdapter(sql,conn);            DataSet ds = new DataSet();            da.Fill(ds, tableName);            CloseConn();            return ds;        }        //返回DataView        public static DataView GetDataViewValue(string sql) {            OpenConn();            SqlDataAdapter da;            DataSet ds = new DataSet();            da = new SqlDataAdapter(sql, conn);            da.Fill(ds, "temp");            CloseConn();            return ds.Tables[0].DefaultView;        }        //返回DataTable        public static DataTable GetDataTableValue(string sql) {            OpenConn();            SqlDataAdapter da = new SqlDataAdapter(sql,conn);            DataTable dt = new DataTable();            da.Fill(dt);            CloseConn();            return dt;        }        //执行一个Sql操作：添加，删除，更新操作        public void ExecuteNonQuery(string sql)        {            OpenConn();            SqlCommand cmd;            cmd = new SqlCommand(sql, conn);            cmd.ExecuteNonQuery();            cmd.Dispose();            CloseConn();        }        //执行一个Sql操作：添加，删除，更新操作，返回受影响行数        public int ExecuteNonQueryCount(string sql)        {            OpenConn();            SqlCommand cmd;            cmd = new SqlCommand(sql, conn);            int value = cmd.ExecuteNonQuery();            return value;        }        //执行一条返回第一条记录第一列的SqlCommand命令        public object ExecuteScalar(string sql)        {            OpenConn();            SqlCommand cmd = new SqlCommand(sql, conn);            object value = cmd.ExecuteScalar();            return value;        }        //返回记录数        public int SqlServerRecordCount(string sql)        {            OpenConn();            SqlCommand cmd = new SqlCommand();            cmd.CommandText = sql;            cmd.Connection = conn;            SqlDataReader dr;            dr = cmd.ExecuteReader();            int RecordCount = 0;            while (dr.Read())            {                RecordCount++;            }            CloseConn();            return RecordCount;        }        //判断是否为数字        public static bool GetSafeValue(string value)        {            if (string.IsNullOrEmpty(value))            {                return false;            }            foreach (char ch in value)            {                if (!char.IsDigit(ch))                {                    return false;                }            }            return true;        }            }}

如此在Form1的监听器方法中，便可调用以上SqlHelp方法，以便响应登录按钮的触发

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;using System.Data.Sql;using System.Data.SqlClient;namespace WindowsFormsApp3{    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        private void label2_Click(object sender, EventArgs e)        {        }        private void label1_Click(object sender, EventArgs e)        {        }        private void button1_Click(object sender, EventArgs e)        {            string accStr = this.textBox1.Text;            string pswStr = this.textBox2.Text;                        if(accStr == "" || pswStr == "")            {                MessageBox.Show("用户名和密码不能为空，请重新输入");            }            else            {                string selectSql = "select * from Login_Table where Account='" + accStr + "' and Password='"+pswStr+"'";                SqlHelp sqlHelper = new SqlHelp();                int count = sqlHelper.SqlServerRecordCount(selectSql);                if (count > 0)//count大于0说明匹配成功                {                    MessageBox.Show("信息验证成功");                    Form2 form = new Form2();                    form.Show();                    this.Hide();                }                else {                    MessageBox.Show("用户名或者密码错误");                }            }        }        private void button2_Click(object sender, EventArgs e)        {            //尚未更新        }        private void button3_Click(object sender, EventArgs e)        {            Application.ExitThread();        }        private void Form1_Load(object sender, EventArgs e)        {            //还没更新        }        private void checkBox1_CheckedChanged(object sender, EventArgs e)        {            if (checkBox1.Checked)            {                textBox2.PasswordChar = new Char();//当勾选框的时候，为显示密码            }            else {                textBox2.PasswordChar = '*';//当不勾选的时候，为密文状态            }        }    }}

二、编写主界面Form2

namespace WindowsFormsApp3{    partial class Form2    {        /// <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);        }        #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.label1 = new System.Windows.Forms.Label();            this.button1 = new System.Windows.Forms.Button();            this.button2 = new System.Windows.Forms.Button();            this.SuspendLayout();            //             // label1            //             this.label1.AutoSize = true;            this.label1.Font = new System.Drawing.Font("宋体", 15F);            this.label1.Location = new System.Drawing.Point(128, 37);            this.label1.Name = "label1";            this.label1.Size = new System.Drawing.Size(287, 25);            this.label1.TabIndex = 0;            this.label1.Text = "欢迎您，您已经成功登录";            //             // button1            //             this.button1.Font = new System.Drawing.Font("宋体", 13F);            this.button1.Location = new System.Drawing.Point(133, 116);            this.button1.Name = "button1";            this.button1.Size = new System.Drawing.Size(75, 33);            this.button1.TabIndex = 1;            this.button1.Text = "确定";            this.button1.UseVisualStyleBackColor = true;            this.button1.Click += new System.EventHandler(this.button1_Click);            //             // button2            //             this.button2.Font = new System.Drawing.Font("宋体", 13F);            this.button2.Location = new System.Drawing.Point(340, 116);            this.button2.Name = "button2";            this.button2.Size = new System.Drawing.Size(75, 33);            this.button2.TabIndex = 2;            this.button2.Text = "退出";            this.button2.UseVisualStyleBackColor = true;            this.button2.Click += new System.EventHandler(this.button2_Click);            //             // Form2            //             this.AutoScaleDimensions = new System.Drawing.SizeF(8F, 15F);            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;            this.ClientSize = new System.Drawing.Size(550, 184);            this.Controls.Add(this.button2);            this.Controls.Add(this.button1);            this.Controls.Add(this.label1);            this.Name = "Form2";            this.Text = "Form2";            this.ResumeLayout(false);            this.PerformLayout();        }        #endregion        private System.Windows.Forms.Label label1;        private System.Windows.Forms.Button button1;        private System.Windows.Forms.Button button2;    }}

主界面控件完成后即可，在“登录”按钮操作下，课进入数据库中比对，如果账号密码比对成功，即可进入Form2登录主界面，否则提示错误。