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updating sql server database using c# in asp.net-Exceptionshub

Posted by: admin February 24, 2020 Leave a comment

Questions:

There isn’t any compile error but the database doesn’t get updated at all. what is wrong with the code?

protected void Page_Load(object sender, EventArgs e) {
    rno.Text = Request.QueryString["rno"];//rno is a textbox


    string connectionString = @"Data Source = (localdb)\MSSQLLocalDB; Initial Catalog = db1; Integrated Security = True";
    SqlConnection cnn = new SqlConnection(connectionString);
    cnn.Open();

    String sql = "select fname from table1 where rno = @rno";

    SqlCommand command = new SqlCommand(sql, cnn);
    command.Parameters.AddWithValue("@rno", rno.Text.Trim());
    SqlDataReader reader = command.ExecuteReader();
    if (reader.Read()) {
        fname.Text = reader["xcountry"].ToString().Trim(); //fname is a textbox
    }
    reader.Close();
    command.Dispose();
    cnn.Close();

    fName.ReadOnly = true;
}

protected void modify_Click(object sender, EventArgs e) {

    fName.ReadOnly = false;
}

protected void savechanges_Click(object sender, EventArgs e) {
    string connectionString = @"Data Source = (localdb)\MSSQLLocalDB; Initial Catalog = db1; Integrated Security = True";
    SqlConnection cnn = new SqlConnection(connectionString);
    cnn.Open();


    String sql = "update table1 set [email protected] where rno = @rno";

    SqlCommand command = new SqlCommand(sql, cnn);
    command.Parameters.AddWithValue("@fname", sfname);
    command.Parameters.AddWithValue("@rno", rno.Text.Trim());

    command.ExecuteNonQuery();
    command.Dispose();
    cnn.Close();
    fName.ReadOnly = true;
}
How to&Answers:

I have tried your code which executed fine and updated database table as well.

I have tried like below :

        string connectionString = @"data source=MS-KIRON-01;initial catalog=TestDatabase;integrated security=True;MultipleActiveResultSets=True";
        SqlConnection cnn = new SqlConnection(connectionString);
        cnn.Open();


        String sql = "update TestTable set [email protected] where rno =rno";

        SqlCommand command = new SqlCommand(sql, cnn);
        command.Parameters.AddWithValue("@fname", "Test");
        command.Parameters.AddWithValue("@rno", "rno");

        command.ExecuteNonQuery();
        command.Dispose();
        cnn.Close();

Another way I have tried.

            using (SqlConnection connection = new SqlConnection(connectionString ))
                    {
                        connection.Open();
                        var queryText = "UPDATE TestTable SET fname = '" + requestPram.fname + "' WHERE rno ='" + requestPram.rno + "'";

                        using (SqlCommand cmd = new SqlCommand(queryText, connection))
                        {
                            responseResults = await cmd.ExecuteNonQueryAsync();
                        }
                        connection.Close();

                    }

Hope it would help

Answer:

After searching for a while, I found out that this code was executing perfectly. The only problem was that everything was inside the page_Load() method and thus the page was reloading everytime I updated the database and thus removing the small window to edit the textboxes. The appropriate solution was to associate this code with some button event rather than with the page_Load() event.