How to update a gridview

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4.00/5 (1 vote)

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I have 2 forms, Form A has text boxes which adds data to the Mysql database.

Form B includes a flexgrid.

When I edit a row in the flexgrid it opens Form A but when I save, it creates another record. I want it to update existing record. On my save button I have

C#

private void lnkSave_Click(object sender, EventArgs e)
        {
             string constring = "datasource=127.0.0.1;Port=3306;Database=bpos;username=root;password=Pass";
            string Query = "insert into bpos.patchtest (Description,Employee,MemberID,Results,Date) values('" + this.txtDescription.Text + "','" + this.cmbEmployee.Text + "','" + this.txtRefNo2.Text + "','" + Results + "','" + this.metroDateTime1.Text + "') ;";
    
            MySqlConnection conDataBase = new MySqlConnection(constring);
             MySqlCommand cmdDataBase = new MySqlCommand(Query, conDataBase);
              MySqlDataReader myReader;
             try
             {
               conDataBase.Open();
              myReader = cmdDataBase.ExecuteReader();
               MessageBox.Show("Saved");
               
               while (myReader.Read())
                {

                 }

              }
             catch (Exception ex)
               {

                   MessageBox.Show(ex.Message);
               }
              }

I don't want to create an Update button. Is it possible to Update using above save button?

What I have tried:

I tried using an update button but I really don't want to use another button.

Posted 4-Oct-16 8:01am

Member 10627757

Updated 4-Oct-16 8:07am

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[no name] 4-Oct-16 14:24pm

"Is it possible", yes it is possible.

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OriginalGriff · Answer 1 · 2016-10-04T08:07:00

Yes - but first don't do it like that! Never concatenate strings to build a SQL command. It leaves you wide open to accidental or deliberate SQL Injection attack which can destroy your entire database. Use Parametrized queries instead.

You can modify rows just by issuing an UPDATE query instead of an INSERT: INSERT always creates a new row, UPDATE only ever changes existing rows.
The rough syntax is:

SQL

UPDATE MyTable SET MyColumn = MyNewValue, MyOtherColumn = MyOtherNewValue WHERE MyROwIDColumn=TheIDOfTheColumnToChange

BTW do yourself a favour: INSERT and UPDATE commands do not return any row data - so using a DataReader is pointless. Instead, these type of commands should be issued with ExecuteNonQuery - which returns the number of rows inserted or changed instead.

And seriously: Go through all your code and get rid of string concatenation - it is really dangerous!