C#编写winform修改用户
1、以XML的方式首先连接数据库，具体连接方式请参考相关文档或小编的上一篇《C#编写winform新增用户》
2、检查要修改密码的用户是否存在。
3、检查输入的旧密码是否正确，这样是防止别人随意去更改他人帐号密码。
4、新密码验证，确保user输入的密码正确。
5、Update 数据库表，并做相关提示。
update Employee set pwd ='" + newpwd + "'where User_id='" + textBox6.Text.Trim() + "'", conn
6、附上完整代码:
private void button2_Click(object sender, EventArgs e)
{
try
{
SqlConnection conn = new SqlConnection(Read_Xml(Application.StartupPath + "\\Sqlconnection.xml"));
conn.Open();
SqlCommand cmd3 = new SqlCommand("select count(*) from Employee where User_id='" + textBox6.Text.Trim() + "'", conn);
int b = (int)cmd3.ExecuteScalar();
if (b == 1)
{
SqlCommand cmd4 = new SqlCommand("select pwd from Employee where User_id='" + textBox6.Text.Trim() + "'", conn);
string c = cmd4.ExecuteScalar().ToString();
string oldpwd = textBox7.Text.Trim();
string newpwd = textBox8.Text.Trim();
string dnewpwd = textBox9.Text.Trim();
if ((b == 1) && (c == oldpwd) && (newpwd == dnewpwd))
{
SqlCommand cmd5 = new SqlCommand("update Employee set pwd ='" + newpwd + "'where User_id='" + textBox6.Text.Trim() + "'", conn);
int k = (int)cmd5.ExecuteNonQuery();
if (k > 0)
{
MessageBox.Show("密码修改成功！", "提示");
}
else
{
MessageBox.Show("密码修改失败！", "提示");
}
}
else
{
MessageBox.Show("新旧密码填写错误，请检查！", "提示");
}
}
else
{
MessageBox.Show("用户名不存在！", "提示");
}
conn.Close();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
