CODEWITHSUNDEEP
c#.netvisual-studio-2010memoryout-of-memory
egrang
egrang

Reputation: 25

Adding a lot of rows in DataGridView causes System.OutOfMemoryException

I am using this code to add rows to my DataGridView from a comma separated formatted string.

public void addRows(ArrayList keywords)
{
    try
    {
        foreach (string keyword in keywords)
        {
            bool already_exists = false;

            string[] row = keyword.Split(',');

            foreach (DataGridViewRow row2 in keywords_grid.Rows)
            {
                string keyword2 = keywords_grid.Rows[row2.Index].Cells[0].Value.ToString().Trim();

                if (row[0] == keyword2)
                {
                    already_exists = true;
                    continue;
                }
            }

            if (already_exists) continue;

            int n = keywords_grid.Rows.Add();

            keywords_grid.Rows[n].Cells[0].Value = row[0];
            keywords_grid.Rows[n].Cells[1].Value = row[1];
            keywords_grid.Rows[n].Cells[2].Value = getSourceIcon(row[2]);
            keywords_grid.Rows[n].Cells[2].ToolTipText = row[2].Trim().ToUpper();

            gridChanged = true;
        }
    }
    catch (Exception ex){}
}

private Icon getSourceIcon(string _color)
{
    string color = _color.ToLower();

    switch (color)
    {
        case "red":
            return Properties.Resources.red_icon;
        case "yellow":
            return Properties.Resources.yellow_icon;
        case "green":
            return Properties.Resources.green_icon;
        case "user input":
            return Properties.Resources.user_input_icon;
        default:
            return Properties.Resources.user_input_icon;
    }
}

I get the error:

An unhandled exception of type 'System.OutOfMemoryException' occurred in System.Windows.Forms.dll

Additional information: Out of memory.

When the rows count is >4000.

I commented each part of the code and found that when I comment this part:

    /*int n = keywords_grid.Rows.Add();

    keywords_grid.Rows[n].Cells[0].Value = row[0];
    keywords_grid.Rows[n].Cells[1].Value = row[1];
    keywords_grid.Rows[n].Cells[2].Value = getSourceIcon(row[2]);
    keywords_grid.Rows[n].Cells[2].ToolTipText = row[2].Trim().ToUpper();*/

The error doesn't occur.

Why is this error happening and how could I avoid it?

Upvotes: 1

Views: 3500

Answers (2)

Thomas Levesque
Thomas Levesque

Reputation: 292425

Don't add the rows manually to the DGV, use either data binding or virtual mode. With either approach, only visible rows will be created, which avoids creating thousands of UI objects

Upvotes: 2

Felice Pollano
Felice Pollano

Reputation: 33252

Usually big grid has to be treated by using virtuial data mode.

Upvotes: 2

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