C#数据库连接操作大全
下面是c#与数据库的连接及增删改除的各种操作，全部经过上机验证。

本人是从事软件开发，如果各位有什么问题或者需要帮助的可以在我的空间留言。

一：数据库连接代码：
SqlConnection objSqlConnection = new SqlConnection ("server = 127.0.0.1;uid = sa; pwd =;database =test");
objSqlConnection.Open();
二：数据库的添加记录代码：
int i = 0;
string s1 = "", s2 = "";
i = Convert.ToInt16(textBox1.Text);
s1 = textBox2.Text;
s2 = textBox3.Text;
SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功", "好");
try
{
SqlCommand sqlcom = new SqlCommand("insert into info(id,name,sex) values( " + i + ",'" + s1 + "','" + s2 + "')", objSqlConnection);
sqlcom.ExecuteNonQuery();
MessageBox.Show("添加成功！", "啊");
}
catch (Exception a)
{
MessageBox.Show(a.ToString());
}
MessageBox.Show("添加成功！", "啊");
}
三：数据库的修改代码：
int i = 0;
string s1 = "", s2 = "";
s1 = textBox2.Text;
s2 = textBox3.Text;
if (textBox1.Text.Length == 0)
i = 0;
else
i = Convert.ToInt32(textBox1.Text);
SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功", "好");
try
{
SqlCommand sqlcom = new SqlCommand("update info set name='"+s1+"',sex='"+s2+"'"+"where id=" + i, objSqlConnection);
sqlcom.ExecuteNonQuery();
MessageBox.Show("修改成功！", "啊");
objSqlConnection.Close();
}
catch (Exception a)
{
MessageBox.Show(a.ToString());
}
四：数据库的删除代码：
int i = 0;
string s1 = "", s2 = "";
s1 = textBox2.Text;
s2 = textBox3.Text;
if(textBox1.Text.Length==0)
i=0;
else
i = Convert.ToInt16(textBox1.Text);
SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功", "好");
try
{
SqlCommand sqlcom = new SqlCommand("delete from info where id="+i, objSqlConnection);
sqlcom.ExecuteNonQuery();
MessageBox.Show("删除成功！", "啊");
objSqlConnection.Close();
}
catch (Exception a)
{
MessageBox.Show(a.ToString());
}
五：数据库的查询代码：
1.类开始：
DataTable dt1 = new DataTable();
SqlDataAdapter da1 = new SqlDataAdapter();
2.按钮代码：
int i = 0,n=0;
string s1 = "", s2 = "";
s1 = textBox2.Text;
s2 = textBox3.Text;
if (textBox1.Text.Length == 0)
i = 0;
else
i = Convert.ToInt32(textBox1.Text);
SqlConnection objSqlConnection = new SqlConnection("server = 127.0.0.1;uid = sa; pwd =;database =test");
objSqlConnection.Open();
MessageBox.Show("数据库连接成功", "好");
string query = "SELECT * from info where id="+i;
DataSet objDataSet = new DataSet();
SqlDataAdapter obj = new SqlDataAdapter();
obj.SelectCommand = new SqlCommand(query, objSqlConnection);
obj.Fill(objDataSet, "info");
SqlCommand objSqlCommand = new SqlCommand(query, objSqlConnection);
SqlDataReader objSqlReader = objSqlCommand.ExecuteReader();
while (objSqlReader.Read())
{
n += 1;
MessageBox.Show("编号: " + objSqlReader.Getvalue(0) + " 姓名:" + objSqlReader.Getvalue(1) + " 性别" + objSqlReader.Getvalue(2));
}
if (n == 0)
MessageBox.Show("数据库中没有这样的记录！");
六：数据库的查询代码：
int i = 0;
// int n = 0;
string s1 = "", s2 = "";
string sql;
s1 = textBox2.Text;
s2 = textBox3.Text;
if (textBox1.Text.Length == 0)
{
i = 0;
}
else
i = Convert.ToInt32(textBox1.Text);。