Hi Mike,

              Your first workaround is great and am using it, thanks for your help!

Hi,

Since you are getting the data Asynchronously, the Combo is determining the size of the dropdown before there is any data or even a data source attached. So it's dropping down, but it's very small.

The second time you drop it down, it has a DataSource and the data is already there, so it can determine the proper size.

Comparing to the MS Combo isn't really a fair test here, since the UltraComboEditor's dropdown size calculation is much more complicated in order to support all the features that the UltraComboEditor has and the MS Combo doesn't. There's no way to force the ultraComboEditor to resize it's list while it is already dropped down.

But I found a couple of potential workarounds for you.

1) Fill the ultraComboEditor with a few dummy items before it is ever dropped down.

        public Form1()
        {
            InitializeComponent();

            for (int i = 0; i < 8; i++)
            {
                this.ultraComboEditor1.Items.Add(0, string.Empty);
            }            
        }

2) Trap for the first time the combo is dropped down and close it up and then drop it down again.

        bool firstDropDown = true;
        private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            DataTable dt = e.Result as DataTable;

            ultraComboEditor1.DataSource = dt;
            ultraComboEditor1.ValueMember = "Value";
            ultraComboEditor1.DisplayMember = "Text";

            if (this.firstDropDown)
            {
                this.firstDropDown = false;
                this.ultraComboEditor1.CloseUp();
                this.ultraComboEditor1.DropDown();
            }
        }

Personally, I like the first one, since with the second one, you get a little bit of a flicker the first time you drop it down.

I have attached an example solution.

Hi Mike, 

              Thanks for the quick reply, here is an example of what i was talking about, you have to click on the ultracomboeditor twice for it to refresh its values, while the plain .net object works fine. I couldn't find any way of fixing this issue..all the form has is two controls, a ultracomboeditor and a combobox, code below

public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        private void ultraComboEditor1_AfterDropDown(object sender, EventArgs e)

        {

            LoadDataTable();

        }

        private void comboBox1_DropDown(object sender, EventArgs e)

        {

            LoadDataTable();

        }

        private void LoadDataTable()

        {

            BackgroundWorker bw = new BackgroundWorker();

            bw.DoWork += new DoWorkEventHandler(bw_DoWork);

            bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);

            bw.RunWorkerAsync();

        }

        private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

        {

            DataTable dt = e.Result as DataTable;

            ultraComboEditor1.DataSource = dt;

            ultraComboEditor1.ValueMember = "Value";

            ultraComboEditor1.DisplayMember = "Text";

            ultraComboEditor1.Invalidate();

            comboBox1.DataSource = dt;

            comboBox1.ValueMember = "Value";

            comboBox1.DisplayMember = "Text";

            comboBox1.Invalidate();

        }

        private void bw_DoWork(object sender, DoWorkEventArgs e)

        {

            DataTable dt = new DataTable();

            dt.Columns.Add("Text", typeof(string));

            dt.Columns.Add("Value", typeof(object));

            for (int i = 0; i <= 1000; i++)

            {

                dt.Rows.Add("Value " + i.ToString(), i);

            }

            e.Result = dt;

        }

    }