Pre-load tabs in a TabControl to speed up tab switching

Question

I have a TabControl with three tabs in it. Each tab contains a DataGridView. When I display the TabControl for the first time, I databind my source data to each of the three DataGridViews and after some delay, the TabControl appears on the screen on the default (1st) tab.

When I click on either of the other two tabs (for the first time only), there is a very lengthy delay before each tab is shown. Once any of the tabs has been displayed at least once, I can freely switch between tabs very quickly. Is there any way that I can pre-load or pre-render these tabs so that I don't experience this delay on the first display?

Perhaps I can do something in a thread in the background to pre-load the remaining tabs. Or perhaps someone has written an extension of the TabControl which does this for me.

Any help is appreciated.

Edit: As requested by krawl, here is the code I am using that binds the data to the DataGridViews.

public void LoadNewDataBase(string filename)
{
    //  Create the database connection
    mySQL.CreateNewDataBase(filename);

    // Display the DF DataSet
    dataGridViewDF.DataSource = GetDataSet("DF").Tables[0].DefaultView;
    dataGridViewSA.DataSource = GetDataSet("SA").Tables[0].DefaultView;
    dataGridViewGPS.DataSource = GetDataSet("GPS").Tables[0].DefaultView;

    dataGridViewDF.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
    dataGridViewSA.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
    dataGridViewGPS.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;

    // Preload the tabs
    for (int i = tabControl1.TabCount - 1; i >= 0; i--)
    {
        tabControl1.SelectedIndex = i;
        tabControl1.Invalidate();
        tabControl1.Update();
    }
}

private DataSet GetDataSet(string tableName)
{
    DataSet ds = new DataSet();
    mySQL.GetDataSet("SELECT * FROM " + tableName).Fill(ds);
    return ds;
}

This operation is not threaded. As a temporary solution to my problem, I included that for loop into my LoadNewDataBase method for iterating over each tab and displaying it. To obfuscate this operation from the user, I overlay a graphic on top of my TabControl to indicate that the control is loading and then I hide it afterwards (code for that not included). It's useful as a workaround but not an elegant solution.

I think BackGround Worker will work here when your app is opening — Rafay Zia Mir
Right but my question is what methods to invoke in order to pre-load the tabs. I can setup the threading or bgWorker. I don't know the methods to call within the threading to do the pre-load. I am also still fairly certain that even if I use threading/bgWorker, I will need to invoke the TabControl to make it paint itself. — Michael Mankus

krawl krawl · Accepted Answer · 2012-08-15T20:55:24

I would suggest posting some code on how you are attempting to load the tabs. I performed a test with the following code with no interface lag whatsoever.

    protected void Form1_Load(object sender, EventArgs e)
    {
        dataGridView1.DataSource = GetTable();
        dataGridView2.DataSource = GetTable();
        dataGridView3.DataSource = GetTable();
    }

    private DataTable GetTable()
    {
        DataTable table = new DataTable();
        for (int i = 0; i < 6; i++)
        {
            table.Columns.Add("Col" + i.ToString(), typeof(string));
        }

        for (int i = 0; i < 1000; i++)
        {
            table.Rows.Add(GetRandomString(), GetRandomString(), GetRandomString(), GetRandomString(), GetRandomString(), GetRandomString());
        }

        return table;
    }


    private Random rand = new Random();
    private string validChars = "0123456789abcdefghijklmnopqurstuvwyz";

    private string GetRandomString()
    {
        StringBuilder builder = new StringBuilder();

        char[] c = new char[rand.Next(15, 20)];
        for (int i = 0; i < c.Length; i++)
        {
            c[i] = validChars[rand.Next(0, validChars.Length - 1)];
        }

        return new string(c);
    }

Pre-load tabs in a TabControl to speed up tab switching

3 Answers