Question

After following the MSDN guide to create a new thread to update a UI control I’m getting a strange error. I had this same query run in the load method and it worked just fine, now running in the new thread I get the right number of results, but instead of getting the names of the fields I just get DataSet written 16 time in my comboBox. Can anyone help me with this?

private void Form1_Load(object sender, EventArgs e)
    {
        recipeListComboBox.Items.Clear();
        Thread QueryThread = new Thread(new ThreadStart(updateRecipeList));
        QueryThread.Start();
    }

 private void updateRecipeList()
    {

        IEnumerable<string> list = recipeList.getList();

        foreach (string a in list)
            UpdateRecipeComboBox(a);
    }

 private void UpdateRecipeComboBox(string text)
    {
        if (this.recipeListComboBox.InvokeRequired)
        {
            UpdateRecipeComboBoxCallBack d = new UpdateRecipeComboBoxCallBack(UpdateRecipeComboBox);
            Invoke(d, new object[] { text });
        }

        else
        {
            this.recipeListComboBox.Items.Add(Text);
        }
    }

    delegate void UpdateRecipeComboBoxCallBack(string text);

before I put this on a new thread it looked like this:

private void Form1_Load(object sender, EventArgs e)
{
     recipeListComboBox.Items.Clear();
     IEnumerable<string> list = recipeList.getList();

     foreach (string a in list)
          recipeComboBox.Items.Add(a);

this would retrun a list of 16 different recipies in the database, now I just get dataSet printed 16 times.

Thanks for any help!!

Craig

Answer 1

If you’re getting "DataSet"printed over an over again I’m guessing that somewhere you’re using a DataSet object in place of a string parameter and it’s calling object.ToString() automatically which returns the name of the class.

Not sure if it’s your problem but you also have a casing mismatch here:

private void UpdateRecipeComboBox(string text)
{
    if (this.recipeListComboBox.InvokeRequired)
    {
        UpdateRecipeComboBoxCallBack d = new UpdateRecipeComboBoxCallBack(UpdateRecipeComboBox);
        Invoke(d, new object[] { text });
    }

    else
    {
        this.recipeListComboBox.Items.Add(Text);  // <--- should be text???
    }
}