CODEWITHSUNDEEP
c#datagridviewdatagrid
Sefa Akbulut
Sefa Akbulut

Reputation: 23

How can I access specific columns of updated rows of on a DataGridView

I'm working on a C# application and using the DataGridView component. My datagrid is connected to my database and loads a single data table. The user fills empty fields and saves the changes on the DataGridView and also database. The question is that I need to use a specific column's index that the user filled.

This is the code that creates the datagrid:

void gridDoldur()
{
    try
    {
        string query = "SELECT DersId FROM Dersler WHERE DersAd= @dersad";
        SqlConnection conn = new SqlConnection("Data Source=SEFA-PC;Initial Catalog=proje;Integrated Security=True;Pooling=False;MultipleActiveResultSets=True");
        SqlCommand comd = new SqlCommand(query, conn);
        comd.Parameters.AddWithValue("@dersad", dersBox.SelectedItem);

        conn.Open();
        SqlDataReader dre;              // dersin adından id'si çekildi
        dre = comd.ExecuteReader();
        dre.Read();
        int dersId = dre.GetInt32(0);  

        dt.Clear();
        sda = new SqlDataAdapter("SELECT * FROM Notlar WHERE DersId=" + dersId, conn);

        sda.Fill(dt);
        notGrid.DataSource = dt;
        notGrid.Visible = true;
        kaydetButton.Visible = true;
        notGrid.Columns[0].Visible = false;
        notGrid.Columns[8].Visible = false;
        notGrid.Columns[1].ReadOnly = true;
        notGrid.Columns[7].ReadOnly = true;

        sBuilder = new SqlCommandBuilder(sda);
        conn.Close();
}

And this is how my grid looks: https://i.sstatic.net/rLagd.jpg

I need to access elements of edited rows.

Upvotes: 2

Views: 487

Answers (2)

OhBeWise
OhBeWise

Reputation: 5454

This may be overkill for your purposes since it will trigger every time any cell in a row is changed, however you can get a general idea from it hopefully. You can easily grab the row index using the DataGridView's CellValueChanged event handler. The idea here would be to note which rows have had a change in this method, like so:

private List<int> editedRows = new List<int>;

private void myDGV_CellValueChanged(object sender, DataGridViewCellEventArgs e)
{
  if (!this.editedRows.Contains(e.RowIndex))
  {
     editedRows.Add(e.RowIndex);
  }
}

With this idea, you could call your method something like this:

foreach (int row in this.editedRows)
{
  this.MyMethod((int)myDGV[row, 0].Value, (int)myDGV[row, 1].Value, (int)myDGV[row, 2].Value, ...);
}

Or:

foreach (int row in this.editedRows)
{
  DataGridViewRow r = myDGV.Rows[row];
  this.MyMethod((int)r.Cells[0].Value, (int)r.Cells[1].Value, (int)r.Cells[2].Value, ...);
}

Note: Remember to cast the cell value to your data type (I assumed int based on the screenshot).

I did't see the context of your method anywhere, so hopefully this gives you a general idea of where to go next.

Edit: I would go with Jeff's answer. It gets the same idea across without the need of manually storing a list of updated rows.

Upvotes: 0

Jeff B
Jeff B

Reputation: 8982

You can spin over the rows on the DataTable and check their DataRowState to determine if they have changed.

foreach (DataRow row in dt.Rows)
{
    if (row.RowState == DataRowState.Modified)
    {
        var infoINeed = (int) row["SomeInformation"];
        var infoByColumnIndex = row[3].ToString();
        // Do stuff
    }
}

dt.AcceptChanges();

Once you are finished with your processing, you'll want to be sure to call AcceptChanges(). This will change the RowState on DataRowState.Modified rows to DataRowState.Unchanged.

Upvotes: 1

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