ShowDialog（）不等待输入

Question

Maybe this problem is very easy for some, but it's bugging me.

The behaviour I am looking for is: - when I select an menu item, a dialog appears; - after the dialog selection is made, a new form is rendered, according to the selection made

This is the code:

        this.panel1.Controls.Clear();
        if (this.childForm != null)
        {
            this.childForm.Dispose();
            this.childForm = null;
        }

        using (var selectionForm = new SelectTransaction())
        {
            var result = selectionForm.ShowDialog();
            childForm = new TransactionForm(selectionForm.transactionName);
            childForm.TopLevel = false;
            this.panel1.Controls.Add(childForm);
            childForm.Location = new Point(0, 0);
            childForm.Show();
        }  

The code work as I want in general. But from time to time, mostly when making the selection twice in a row, the ShowDialog() does not wait for my input. It goes righ to showing the form.

I tried to create and dispose the selection object myself (instead of using using ) but the same problem occurs.

The dialog result is set in SelectTransaction form. In there I have a combobox and when I select an item, I return the result.

public partial class SelectTransaction : Form
{
    public string transactionName;

    public SelectTransaction()
    {
        InitializeComponent();

        // The data set is retrieving from a database

        selectTransactionComboBox.Text = " - SELECT TRANSACTION - ";
        selectTransactionComboBox.Items.Clear();
        for (int i = 0; i < dataSet.Tables["TransactionInfo"].Rows.Count; i++)
        {      
            selectTransactionComboBox.Items.Add(dataSet.Tables["TransactionInfo"].Rows[i].ItemArray.GetValue(0).ToString());
         }  
    }

    private void comboBox1_SelectedIndexChanged(object sender, EventArgs e)
    {
        this.transactionName = selectTransactionComboBox.Items[selectTransactionComboBox.SelectedIndex].ToString();
        this.Close();
    }
}

Can someone tell me what I am doing wrong?

Answer 1

Sometimes the SelectedIndexChanged-Event can fire while you fill the combobox. Instead use the SelectionChangeCommitted-Event http://msdn.microsoft.com/en-us/library/system.windows.forms.combobox.selectionchangecommitted.aspx

Or another solution: Don't add the event listener in your form, just add it after you populate the combobox (after you finished the For-Loop)

selectTransactionComboBox.SelectedIndexChanged += comboBox1_SelectedIndexChanged