Question

C#中从SQL中查询到一个字段值怎么赋值给textBox2.Text

[DllImport("User32.dll")]
public static extern int MessageBox(int h, string m, string c, int type);
public SqlConnection cn = new SqlConnection("server=.;database=db_ldsztj;user id=sa;password=");
public ModifyPassword()
{
InitializeComponent();
}

private void button3_Click(object sender, EventArgs e)
{
if (textBox1.Text.Trim()=="")
MessageBox(0, "点击‘查询’按钮前，请先输入用户编码！", "提示！", 0);
else
{
cn.Open();
SqlCommand cmd = new SqlCommand("", cn);
cmd.CommandText = "select * from db_ldsztj.dbo.tb_userlist where id='" + textBox1.Text.Trim() + "'";
if (null == cmd.ExecuteScalar())
MessageBox(0, "你输入的用户编码系统中不存在，请先输入正确的用户编码！", "提示！", 0);
else
{
textBox2.Text = "select username from tb_userlist where id='" + textBox1.Text.Trim() + "'";
textBox5.Text = "select quan from tb_userlist where id='" + textBox1.Text.Trim() + "'";
}
cn.Close();
}
结果：怎么点击“查询“按钮后，textBox2和textBox5分别显示的是 赋值给它的SQL查询语句了，比如：textBox2框中显示的是select username from tb_userlist where id='001'
结果：比如：textBox2框中显示的是lilinjun,操作员才对，语句在SQL2000中执行结果是显示lilinjun的
谢谢了，我找到原因了，再加上
string textbox2 = "select username from tb_userlist where id='" + textBox1.Text.Trim() + "'";
SqlDataAdapter sqlDataAdapter = new SqlDataAdapter(textbox2, cn);
DataSet ds = new DataSet();
sqlDataAdapter.Fill(ds);
string username = ds.Tables[0].Rows[0]["username"].ToString();
this.textBox2.Text = username;
cn.Close();
就可以了

Answer 1

this.textBox2.Text = ds.Table[0]["username"].ToString();//赋值给TextBox2.[username]为数据库中字段
select username from tb_userlist where id='001' 若要显示为你特定的形式。除非001在数据库中是字符型，否则你要在后台进行拼接才能显示其001，否则只会显示为1

Answer 2

你这里写的给它赋一个字符串，当然就显示一个字符串咯
textBox2.Text = "select username from tb_userlist where id='" + textBox1.Text.Trim() + "'";

要改为： textBox2.Text = cmd.ExecuteScalar()+"";

追问

谢谢