您应使用SqldataReader

You should use SqldataReader

SqlCommand cmd = new SqlCommand("select * from Table1",conObject);
            SqlDataReader dr = cmd.ExecuteReader();
            dr.Read();
            if (TextBox1.Text == dr.GetString(0)) // 0 is 1st column
            { 
             //Do as your wish
            }}

我忘了引用引号了:

I forget to mention quotes:

Da = new SqlDataAdapter("select * from tblorder where bookingdate=''" + txtform.text + "''",con1);