how to retrieve data from database in c# windows application

Question

1.00/5 (1 vote)

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C#

private void button2_Click(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection("Data Source=ROHIT-PC\\SQLEXPRESS;Initial Catalog=FMS;Integrated Security=True");
          
             SqlCommand cmd = new SqlCommand("select * from JUNIOR_STUDENT where @UID='+ @ " + txtUid.Text.Trim() + "'",con);
             cmd.CommandType = CommandType.Text;
             cmd.Parameters.AddWithValue("@UId", txtUid.Text);
             cmd.Parameters.AddWithValue("@NAME", txtName.Text);
             cmd.Parameters.AddWithValue("@ROLL_NO", txtRoll.Text);
             cmd.Parameters.AddWithValue("@STREAM", txtStream.Text);
             cmd.Parameters.AddWithValue("@GENDER", txtGender.Text);
             cmd.Parameters.AddWithValue("@YEAR_ID", cbxYearname.Text);
             cmd.Parameters.AddWithValue("@REMARKS", txtRemarks.Text);
             cmd.Parameters.AddWithValue("@ADMISSION_DATE", mtxtAdmsndate.Text);
             cmd.Parameters.AddWithValue("@ACADEMIC_YEAR", txtAcademicYear.Text);
             cmd.Parameters.AddWithValue("@ADMISSION_TYPE", txtAdmissiontype.Text);
             cmd.Parameters.AddWithValue("@CATEGORY_ID", cbxCategory.Text);
             cmd.Parameters.AddWithValue("@SUB_CATEGORY", txtName.Text);
             cmd.Connection = con;
             con.Open();
             
             SqlDataReader reader = cmd.ExecuteReader();
              while (reader.Read())
              {
              txtName.Text=reader["NAME"].ToString();
              txtRoll.Text = reader["ROLL_NO"].ToString();
              txtStream.Text = reader["STREAM"].ToString();
              txtGender.Text = reader["GENDER"].ToString();
              cbxYearname.Text = reader["YEAR_ID"].ToString();
              txtRemarks.Text = reader["REMARKS"].ToString();
              mtxtAdmsndate.Text = reader["ADMISSION_DATE"].ToString();
              txtAcademicYear.Text = reader["ACADEMIC_YEAR"].ToString();
              txtAdmissiontype.Text = reader["ADMISSION_TYPE"].ToString();
              cbxCategory.Text = reader["CATEGORY_ID"].ToString();
              txtSubcategory.Text = reader["SUB_CATEGORY"].ToString();
              
              
              reader.Close();
              con.Close();
              MessageBox.Show("Student : " + txtName.Text + " Transfer of Subject Successfull ", "Student Information", MessageBoxButtons.OK, MessageBoxIcon.Information);
           }
                  }

it show nothing wat can i do ??

Posted 5-May-14 8:36am

Member 10794814

Updated 5-May-14 10:19am

Sander Rossel

v3

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Comments

José Amílcar Casimiro 5-May-14 16:24pm

Sorry for the stupid question, but did you check that you had data in Db, right?

Member 10794814 6-May-14 0:31am

@ Jose Amilcar Ferreira Cassimiro
yes it is... it has some value

Maciej Los 5-May-14 16:36pm

What you mean by "show nothing"?

Member 10794814 6-May-14 0:31am

its show nothing when i click on search button ,the value is not display in respective textbox.
any suggestion ???

Ishpreet Kaur 6-May-14 2:19am

Sql query is not in proper format. That's why it is not showing result.

You have written:

select * from JUNIOR_STUDENT where @UID='+ @ " + txtUid.Text.Trim()

and this is wrong after Where clause.. You have written : "where @uid"

You should write:
where uid=....

not write @ before uid

Member 10794814 11-May-14 1:25am

thank you

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Maciej Los · Answer 1 · 2014-05-05T10:41:00

You did not provide enough information about your issue.

Does the reader contains anything? No! Have a look at your query:

C#

"select * from JUNIOR_STUDENT where @UID='+ @ " + txtUid.Text.Trim() + "'"

Your query should be:

SQL

select [Name], RollNo, Stream, Gender, Year_ID, Remarks, Admission_Date, Academic_Year, Admission_tye, Category_ID, Sub_Category
from JUNIOR_STUDENT
where UID=@UID

Finally, you are using only ine parameter @UID, so why do you set [Name], Rollno, etc?

BTW: Name is a reserved word, use it with brackets!

Corrected code:

C#

SqlCommand cmd = new SqlCommand("select * from JUNIOR_STUDENT where UDI=@UID",con);
             cmd.CommandType = CommandType.StoredProcedure;
             cmd.Parameters.AddWithValue("@UId", txtUid.Text);
             con.Open();
             SqlDataReader reader = cmd.ExecuteReader();

Here is a basic idea: HOW TO: Call SQL Server Stored Procedures in ASP.NET by Using Visual C# .NET[^]. It's true, it's ASP.NET, but the logic is the same!