c#连接数据库的增删改查
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！！！！！！！！！！！！
