1、数据库连接好
2、using System;using System.Collections.Generic;using System.ComponentModel;using System.Data;using System.Data.SqlClient;using System.Drawing;using System.Linq;using System.Text;using System.Windows.Forms;namespace login{ public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=user1;Integrated Security=True"); try { conn.Open(); // 打开数据库连接 //cmd.Connection = conn; //cmd.CommandText = "delete from usermessage"; //cmd.ExecuteNonQuery(); // string str = "insert into usermessage(num,name,tel) values('10091', '张三','3332')"; string str = "insert into usermessage(num,name,tel) values('" + textBox1.Text + "','" + textBox2.Text + "','" + textBox3.Text + "')"; SqlCommand cmd = new SqlCommand(str, conn); cmd.ExecuteNonQuery(); string str1 = "select * from usermessage where num=" + textBox1.Text + ""; SqlCommand cmd1 = new SqlCommand(str1, conn); SqlDataReader reader = cmd1.ExecuteReader(); if (reader.Read()) { MessageBox.Show("添加成功！", "提示"); textBox1.Text = ""; textBox2.Text = ""; textBox3.Text = ""; } reader.Close(); conn.Close(); } catch (Exception ex) { MessageBox.Show("错误信息：" + ex.Message, "出现错误"); } } private void button2_Click(object sender, EventArgs e) { SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=user1;Integrated Security=True"); try { conn.Open(); string str1 = "select * from usermessage where num=" + textBox1.Text + ""; SqlCommand cmd1 = new SqlCommand(str1, conn); SqlDataReader reader = cmd1.ExecuteReader(); if (reader.Read()) { reader.Close(); string str = "delete from usermessage where num='" + textBox1.Text + "'"; SqlCommand cmd = new SqlCommand(str, conn); cmd.ExecuteNonQuery(); MessageBox.Show("删除成功！", "提示"); textBox1.Text = ""; textBox2.Text = ""; textBox3.Text = ""; conn.Close(); } else { MessageBox.Show("用户不存在！", "提示"); textBox1.Text = ""; textBox2.Text = ""; textBox3.Text = ""; } } catch (Exception ex) { MessageBox.Show("错误信息：" + ex.Message, "出现错误"); } } private void button3_Click(object sender, EventArgs e) { SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=user1;Integrated Security=True"); try { conn.Open(); // 打开数据库连接 string str1 = "select * from usermessage where num=" + textBox1.Text + ""; SqlCommand cmd1 = new SqlCommand(str1, conn); SqlDataReader reader = cmd1.ExecuteReader(); if (reader.Read()) { String name = reader["name"].ToString(); String tel = reader["tel"].ToString(); textBox2.Text = name.Trim(); textBox3.Text = tel.Trim(); } else { MessageBox.Show("用户不存在！", "提示"); textBox1.Text = ""; } reader.Close(); conn.Close(); } catch (Exception ex) { MessageBox.Show("错误信息：" + ex.Message, "出现错误"); } } private void button4_Click(object sender, EventArgs e) { SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=user1;Integrated Security=True"); try { int t=0; conn.Open(); if (t == 0) { string str = "update usermessage set name='" + textBox2.Text + "', Tel='" + textBox3.Text + "'where num='" + textBox1.Text + "'"; SqlCommand cmd = new SqlCommand(str, conn); cmd.ExecuteNonQuery(); t++; ; } if(t==1) { string str1 = "select * from usermessage where num=" + textBox1.Text + ""; SqlCommand cmd1 = new SqlCommand(str1, conn); SqlDataReader reader = cmd1.ExecuteReader(); if (reader.Read()) { String name = reader["name"].ToString(); String tel = reader["tel"].ToString(); textBox2.Text = name.Trim(); textBox3.Text = tel.Trim(); reader.Close(); t=0; MessageBox.Show("修改成功！", "提示"); textBox1.Text = ""; textBox2.Text = ""; textBox3.Text = ""; } else { MessageBox.Show("用户不存在！", "提示"); textBox1.Text = ""; textBox2.Text = ""; textBox3.Text = ""; } } } catch (Exception ex) { MessageBox.Show("错误信息：" + ex.Message, "出现错误"); } } private void button5_Click(object sender, EventArgs e) { textBox1.Text = ""; textBox2.Text = ""; textBox3.Text = ""; } private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e) { } private void button6_Click(object sender, EventArgs e) { try { DataGridView dataGridView1 = new DataGridView(); string strsql = "select * from usermessage";//查询语句。 SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=user1;Integrated Security=True"); SqlCommand cmd = new SqlCommand(strsql, conn); SqlDataAdapter da = new SqlDataAdapter(cmd); DataSet ds = new DataSet(); da.Fill(ds); this.dataGridView1.DataSource = ds.Tables[0]; this.dataGridView1.Columns[0].HeaderText = "序号"; this.dataGridView1.Columns[1].HeaderText = "编码"; this.dataGridView1.Columns[2].HeaderText = "姓名"; this.dataGridView1.Columns[3].HeaderText = "电话"; this.dataGridView1.Columns[0].Width = 110; //设置该列宽度 this.dataGridView1.Columns[1].Width = 110; this.dataGridView1.Columns[2].Width = 110; this.dataGridView1.Columns[3].Width = 110; int coun = this.dataGridView1.RowCount; for (int i = 0; i < coun - 1; i++) { this.dataGridView1.Rows[i].Cells[0].Value = i + 1; this.dataGridView1.Rows[i].Cells["id"].Value = i + 1; } //默认按顺序每列DataGridView依次从ds中对应赋值 this.dataGridView1.Columns[0].DataPropertyName = ds.Tables[0].Columns[0].ToString(); } catch (Exception ex) { MessageBox.Show("错误信息：" + ex.Message, "出现错误"); } } private void Form1_Load(object sender, EventArgs e) { DataGridView dataGridView1 = new DataGridView(); string strsql = "select * from usermessage"; SqlConnection conn = new SqlConnection("Data Source=.;Initial Catalog=user1;Integrated Security=True"); SqlCommand cmd = new SqlCommand(strsql, conn); SqlDataAdapter da = new SqlDataAdapter(cmd); DataSet ds = new DataSet(); da.Fill(ds); this.dataGridView1.DataSource = ds.Tables[0]; this.dataGridView1.Columns[0].HeaderText = "序号"; this.dataGridView1.Columns[1].HeaderText = "编码"; this.dataGridView1.Columns[2].HeaderText = "姓名"; this.dataGridView1.Columns[3].HeaderText = "电话"; this.dataGridView1.Columns[0].Width = 110; //设置该列宽度 this.dataGridView1.Columns[1].Width = 110; this.dataGridView1.Columns[2].Width = 110; this.dataGridView1.Columns[3].Width = 110; int coun = this.dataGridView1.RowCount; for (int i = 0; i < coun - 1; i++) { this.dataGridView1.Rows[i].Cells[0].Value = i + 1; this.dataGridView1.Rows[i].Cells["id"].Value = i + 1; } //默认按顺序每列DataGridView依次从ds中对应赋值 this.dataGridView1.Columns[0].DataPropertyName = ds.Tables[0].Columns[0].ToString(); } }}
3、这是结果！！！！！！！！！！！！
