what must i rectify in this code?

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C#

private void button1_Click(object sender, EventArgs e)
        {
            command.Parameters.AddWithValue("@StudentID", textBox1.Text);
            command.Parameters.AddWithValue("@Name", textBox2.Text);
            command.Parameters.AddWithValue("@Age", textBox3.Text);
            command.Parameters.AddWithValue("@Gender", textBox4.Text);
            command.Parameters.AddWithValue("@Courseno",comboBox1.Text);
            command.CommandText = "INSERT into details"+ "(StudentID,Name,Age,Gender,Courseno)VALUES" + "(@StudentID,@Name,@Age,@Gender,@Courseno)";

            try
            {
                con.Open();

                int result = command.ExecuteNonQuery();

                if (result > 0)
                    MessageBox.Show("student successfully updated");
                else
                    MessageBox.Show("failed to update");
            }
            catch (SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                con.Close();
            }

            ClearFields();
        }

When i enter one set of details and click the button, it updates the database. but I am unable to enter a second set of details the second time around. It says @StudentID has already been declared.

Posted 23-Aug-12 0:32am

codingisok101

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Comments

pramod.hegde 23-Aug-12 6:39am

Are you trying to insert the record for the same StudentID? If StudentID is a primary key, then the insert statement would fail, as primary key should be unique.

codingisok101 23-Aug-12 6:45am

no the problem was that everytime i entered one set of records, i could not enter another set of records even after clicking the button. the previous set of records still existed in the form

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Santhosh Kumar Jayaraman · Accepted Answer · 2012-08-23T00:35:00

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C#

command.Parameters.Clear();

C#

private void button1_Click(object sender, EventArgs e)
        {
            command.Parameters.AddWithValue("@StudentID", textBox1.Text);
            command.Parameters.AddWithValue("@Name", textBox2.Text);
            command.Parameters.AddWithValue("@Age", textBox3.Text);
            command.Parameters.AddWithValue("@Gender", textBox4.Text);
            command.Parameters.AddWithValue("@Courseno",comboBox1.Text);
            command.CommandText = "INSERT into details"+ "(StudentID,Name,Age,Gender,Courseno)VALUES" + "(@StudentID,@Name,@Age,@Gender,@Courseno)";

            try
            {
                con.Open();

                int result = command.ExecuteNonQuery();

                if (result > 0)
                    MessageBox.Show("student successfully updated");
                else
                    MessageBox.Show("failed to update");
            }
            catch (SqlException ex)
            {
                MessageBox.Show(ex.Message);
            }
            finally
            {
                con.Close();
                command.Parameters.Clear()
            }

            ClearFields();
        }