c#窗体操作入门代码（自己归纳的，很实用）

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Text; using System.Windows.Forms; using System.Data.SqlClient; namespace WindowsApplication1 { public partial class login : Form { SqlConnection sqlConnection1; SqlDataAdapter sqlDataAdapter1; DataSet DS; DataTable DT; public login() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { string st; st = comboBox1.Text.ToString(); string strPwd = ""; strPwd = textBox1.Text.ToString(); for (int i = 0; i < DT.Rows.Count; i++) { if (st.Trim() == DT.Rows[i]["用户姓名"].ToString().Trim()) { if (strPwd.Trim() == DT.Rows[i]["密码"].ToString().Trim()) { this.DialogResult = DialogResult.OK;//成功 //在Program.cs中写 // static void Main() //{ //Application.EnableVisualStyles(); //Application.SetCompatibleTextRenderingDefault(false); // login fm = new login(); //if (fm.ShowDialog() == DialogResult.OK) // { // Application.Run(new FrmMain()); // } //login form1 = new login (); //form1.Close(); //FrmMain form2 = new FrmMain (); //form2.Show(); } else { MessageBox.Show("你的用户名或密码不正确,请重新输入!"); return; } } //comboBox1.Items.Add(DT.Rows[i]["用户姓名"]); } } private void login_Load(object sender, EventArgs e) { string strConn = "Data Source=HOMEWELL-25A668;Initial Catalog=building;Integrated Security=True"; string sql = " select * from 权限信息表 "; sqlConnection1 = new SqlConnection(strConn); sqlDataAdapter1 = new SqlDataAdapter(sql, sqlConnection1); DS = new DataSet("TableTmp"); sqlDataAdapter1.Fill(DS, "TableTmp"); DT = DS.Tables["TableTmp"]; for (int i = 0; i < DT.Rows.Count; i++) { comboBox1.Items.Add(DT.Rows[i]["用户姓名"]); comboBox1.SelectedIndex = 0;//显示数据库的第一行数据 } } private void textBox1_TextChanged(object sender, EventArgs e) { } } }