String constr = "data source=.;initial Catalog=DB1;user id=sa;password=123";
            SqlConnection conn = new SqlConnection(constr);
            string strcommand = "insert into Cuser(Cname)values('" + UserNameTxt.Text + "')";
            SqlCommand cmd = new SqlCommand(strcommand, conn);
            if (conn.State.Equals(ConnectionState.Closed))
            { conn.Open(); }
            if (UserNameTxt.Text == "sa")          //判断是否登录名为sa
            {
                MessageBox.Show("登录成功！", "登录确认");
                this.panel1.Controls.Clear();      //初始化主panel
                main main = new main();
                main.TopLevel = false;              //设置属性
                main.Show();                        //显示form
                this.panel1.Controls.Add(main);    //把from添加到容器里面里
            }
            else
            {
                MessageBox.Show("登录失败！", "登录确认");
            }
            if (conn.State.Equals(ConnectionState.Open))
            { conn.Close(); }

SqlConnection conn = new SqlConnection();
conn.ConnectionString = sqlb.ConnectionString;
conn.Open();
 string sqlstr="";
SqlDataAdapter adap = new SqlDataAdapter(sqlstr, conn);
DataSet ds = new DataSet();
adap.Fill(ds);
DataTable dt = ds.Tables[0];
if(dt.Rows.Count==1)
{
MainForm2 mf = new MainForm2();
mf.Show();
this.Hide();
}

string sqlstr = "delete from d_user where realname='" + username + "'";
SqlCommand scd = new SqlCommand(sqlstr, conn);
int n = scd.ExecuteNonQuery();
if (n > 0)
{
MessageBox.Show("删除成功!");
}

String con = "data source=.;initial Catalog=DB1;user id=sa;password=123";
            SqlConnection conn = new SqlConnection(con);
            string sql = "insert into pic(姓名,编号,部门,登录密码,职位,电话,住址,QQ) values('" +textBox1.Text + "','" + textBox2.Text + "','" + textBox3.Text + "','" + textBox4.Text + "','" + textBox5.Text + "','" + textBox6.Text + "','" + textBox7.Text + "','" + textBox8.Text + "')"; 
            try
            {
                if (!textBox1.Text.Equals(string.Empty))
                {
                    SqlCommand cmd = new SqlCommand(sql, conn);
                    conn.Open();
                    if (cmd.ExecuteNonQuery() > 0) MessageBox.Show("添加成功");
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message, "添加失败");
            }
            finally
            {
                conn.Close();
            }
string sqlstr = "insert into d_user (username,dep,realname,cpnum,password,major) values (" + "'" + t_logname + "'," + "'" + t_dep + "'," + "'" + t_name + "','"+t_cpnum+"','"+"123','"+t_major+"')";
SqlCommand sqlcmd = new SqlCommand(sqlstr, conn);
n = sqlcmd.ExecuteNonQuery();
if (n > 0)
{
MessageBox.Show("保存成功");
}
else
{
MessageBox.Show("保存失败");
}

string SQLstr = "update cslist set bzdm='" + bzdmstr + "',cs_content='" + bznrstr + "',bzfl='"+bzflstr+"',locationx='"+rowstr+"',locationy='"+colstr+"' where bzdm='"+bzdm+"'";
// MessageBox.Show(SQLstr);
SqlCommand sqlcmd = new SqlCommand(SQLstr, conn);
int n;
n = sqlcmd.ExecuteNonQuery();
if (n > 0)
{
MessageBox.Show("修改成功");
}