C# and SQL data duplication

Question

I have code that is pulling information from SQL server and displaying information about cars.

The problem is that the data is displayed but duplicated. The SQL Data has no duplications but the list boxes are displaying the same data twice.

The code is as follows:

private void Show_Click(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection("Data Source=XXXX");
            DataTable dt = new DataTable();
            SqlDataAdapter SDA = new SqlDataAdapter("SELECT Number_Plate,Registered_Keeper,Make,Model,Year_Of_Make,Colour,Engine_Size,Transmission,Fuel_Type FROM datatable WHERE Number_Plate like '%" + label1.Text + "%'", conn);
            SDA.Fill(dt);
            if (SDA.Fill(dt) == 0)
            {

                button5.Visible = false;
                button4.Visible = true;
                label11.Visible = true;
                Show.Visible = false;
                button3.Visible = true;
                Make.Visible = false;
                Model.Visible = false;
                Year_Of_Make.Visible = false;
                Colour.Visible = false;
                Engine_Size.Visible = false;
                Transmission.Visible = false;
                Fuel_Type.Visible = false;
                Registered_Keeper.Visible = false;
                Plate.Visible = false;
                label2.Visible = false;
                label3.Visible = false;
                label4.Visible = false;
                label5.Visible = false;
                label6.Visible = false;
                label7.Visible = false;
                label8.Visible = false;
                label9.Visible = false;
                label12.Visible = false;
            }
            else
            {
                Plate.DataSource = dt;
                Plate.DisplayMember = "Number_Plate";

                Make.DataSource = dt;
                Make.DisplayMember = "Make";

                Model.DataSource = dt;
                Model.DisplayMember = "Model";

                Year_Of_Make.DataSource = dt;
                Year_Of_Make.DisplayMember = "Year_Of_Make";

                Colour.DataSource = dt;
                Colour.DisplayMember = "Colour";

                Engine_Size.DataSource = dt;
                Engine_Size.DisplayMember = "Engine_Size";

                Transmission.DataSource = dt;
                Transmission.DisplayMember = "Transmission";

                Fuel_Type.DataSource = dt;
                Fuel_Type.DisplayMember = "Fuel_Type";

                Registered_Keeper.DataSource = dt;
                Registered_Keeper.DisplayMember = "RegIstered_Keeper";

                Show.Visible = false;
                button3.Visible = true;
            }

        }

Note: When I add the data in SQL the primary key is missing about 20 numbers, so my data is 20 cars, but when I add a new one its primary key is around 50.

Bennor McCarthy · Accepted Answer · 2013-03-19 21:06:05Z

3

Well, you do SDA.Fill(dt) twice. Try removing the one on the line before the if.

...
SqlDataAdapter SDA = ...
if (SDA.Fill(dt) == 0)
...

edited Mar 19, 2013 at 21:06

Bennor McCarthy

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answered Mar 19, 2013 at 21:05

fredrik

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2 Comments

RobH Over a year ago

Just for completeness - one could also define the DataTable to have a primary key and then calling fill multiple times will update the table rather than append new rows. Also... Sql injection: "...WHERE Number_Plate like '%" + label1.Text + "%'".

fredrik Over a year ago

Correct, on both accounts.

Stokedout · Accepted Answer · 2013-03-19 21:05:43Z

1

you are calling SDA.Fill(dt); twice, once outside, once inside the if statement,

answered Mar 19, 2013 at 21:05

Stokedout

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Comments

Jhigs · Accepted Answer · 2013-03-19 21:10:13Z

1

SDA.Fill(dt) was called 2 times, try to change it to dt.count < 1

answered Mar 19, 2013 at 21:10

Jhigs

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