Leave Event is called more than once in C#

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I have the below code

C#

public void panel_item_collections_Click(object sender, EventArgs e)

        {



TextBox[] textbox_item_array = new TextBox[5];

            item_textbox.Add(textbox_item_array);

            textbox_item_array[0] =

new TextBox();

            textbox_item_array[0].Width = label_item_code.Width;

            textbox_item_array[0].Height = 26;

            textbox_item_array[0].Font = print_font_default;

            textbox_item_array[0].Location =

new Point(label_item_code.Location.X, 45 + (20 * row_count));

            textbox_item_array[0].Name =

string.Concat("item_code", row_count.ToString());

            panel_item_collections.Controls.Add(textbox_item_array[0]);

            textbox_item_array[0].Leave +=

new EventHandler(dynamic_text_item_code_Leave);

            textbox_item_array[0].KeyDown +=

new KeyEventHandler(bill_new_Form_KeyPress);

            textbox_item_array[0].DoubleClick +=

new EventHandler(bill_new_Form_DoubleClick);

            textbox_item_array[1] =

new TextBox();

            textbox_item_array[1].Width = label_item_descrition.Width;

            textbox_item_array[1].Font = textbox_item_array[0].Font;

            textbox_item_array[1].Location =

new Point(label_item_descrition.Location.X, textbox_item_array[0].Location.Y);

            textbox_item_array[1].Name =

string.Concat("item_description", row_count.ToString());

            panel_item_collections.Controls.Add(textbox_item_array[1]);

            textbox_item_array[2] =

new TextBox();

            textbox_item_array[2].Width = label_item_price.Width;

            textbox_item_array[2].Font = textbox_item_array[0].Font;

            textbox_item_array[2].Location =

new Point(label_item_price.Location.X, textbox_item_array[0].Location.Y);

            textbox_item_array[2].Name =

string.Concat("item_price", row_count.ToString());

            panel_item_collections.Controls.Add(textbox_item_array[2]);

            textbox_item_array[3] =

new TextBox();

            textbox_item_array[3].Width = label_item_quantity.Width;

            textbox_item_array[3].Font = textbox_item_array[0].Font;

            textbox_item_array[3].Location =

new Point(label_item_quantity.Location.X, textbox_item_array[0].Location.Y);

            textbox_item_array[3].Name =

string.Concat("item_quantity", row_count.ToString());

            panel_item_collections.Controls.Add(textbox_item_array[3]);

            textbox_item_array[4] =

new TextBox();

            textbox_item_array[4].Width = label_item_total.Width;

            textbox_item_array[4].Font = textbox_item_array[0].Font;

            textbox_item_array[4].Location =

new Point(label_item_total.Location.X, textbox_item_array[0].Location.Y);

            textbox_item_array[4].Name =

string.Concat("item_total", row_count.ToString());

            panel_item_collections.Controls.Add(textbox_item_array[4]);

            row_count++;

        }

C#

void dynamic_text_item_code_Leave(object sender, EventArgs e)
{
    //MessageBox.Show(((Control)sender).Name.Substring(((Control)sender).Name.Length - 1, 1));
    int i;
    string name_textbox = ((Control)sender).Name;
    i = System.Convert.ToInt32(name_textbox.Substring(name_textbox.Length - 1, 1));
    //MessageBox.Show(i.ToString());
    //i--;
    TextBox[] textbox_item_array = new TextBox[5];
    textbox_item_array = (TextBox[])(item_textbox[i]);
    double item_total;
    Item item = new Item();
    //textbox_item_array[0].Leave -= dynamic_text_item_code_Leave;
    if (long.TryParse(textbox_item_array[0].Text, out item.item_code) == true)
    {
        if (item.get_item() == 0)
        {
            textbox_item_array[1].Text = item.item_details;
            textbox_item_array[2].Text = item.sell_price.ToString();
            textbox_item_array[3].Text = "1";
            item_total = System.Convert.ToInt32(textbox_item_array[3].Text) * item.sell_price;
            textbox_item_array[4].Text = item_total.ToString();
        }
    }
    else
    {
        //TextBox[] textbox_item_array = new TextBox[5];
        textbox_item_array = (TextBox[])(item_textbox[item_textbox.Count - 1]);
        panel_item_collections.Controls.Remove(textbox_item_array[0]);
        //textbox_item_array[0].Leave -= dynamic_text_item_code_Leave;
        panel_item_collections.Controls.Remove(textbox_item_array[1]);
        panel_item_collections.Controls.Remove(textbox_item_array[2]);
        panel_item_collections.Controls.Remove(textbox_item_array[3]);
        panel_item_collections.Controls.Remove(textbox_item_array[4]);
        item_textbox.RemoveAt((item_textbox.Count - 1));
        //MessageBox.Show("Deleted");
        //textbox_item_array[0].Leave -= dynamic_text_item_code_Leave;
        //MessageBox.Show(item_textbox.Count.ToString());
        row_count--;
    }
}

Now, the problem is like this:
If the user leave the textbox blank, the row will be deleted. The strange problem is:
If press tab, it will execute the leave event handler twice. It means it will try to delete the same textbox twice and this will create problem. Can any one help me how to avoid this double calling?

Thanks

Posted 7-Jun-13 1:47am

Member 9646334

Updated 19-Nov-17 20:55pm

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Comments

ZurdoDev 7-Jun-13 8:55am

What does the call stack look like? Put a breakpoint and see if the call stack will indicate why it was called?

Member 9646334 7-Jun-13 9:04am

I put break point but it was not mentioned. Please help how can I do that

Sergey Alexandrovich Kryukov 7-Jun-13 10:15am

Look the Debug Window "Call Stack".
—SA

Member 9646334 7-Jun-13 9:15am

I tried to put the break point and it was just the event before it.

Alexander Dymshyts 7-Jun-13 9:18am

Did you try to put e.Handled = true at the end of your event?

Member 9646334 7-Jun-13 10:10am

It is not supported. e.Handled is not supported.

Member 9646334 7-Jun-13 10:23am

Now, I will give exactly how it is executed:
void dynamic_text_item_code_Leave(object sender, EventArgs e)
{
//MessageBox.Show(((Control)sender).Name.Substring(((Control)sender).Name.Length - 1, 1));
int i;
string name_textbox = ((Control)sender).Name;
i = System.Convert.ToInt32(name_textbox.Substring(name_textbox.Length - 1, 1));
//MessageBox.Show(i.ToString());
//i--;
TextBox[] textbox_item_array = new TextBox[5];
textbox_item_array = (TextBox[])(item_textbox[i]);
double item_total;
Item item = new Item();
if (long.TryParse(textbox_item_array[0].Text, out item.item_code) == true)
{
if (item.get_item() == 0)
{
textbox_item_array[1].Text = item.item_details;
textbox_item_array[2].Text = item.sell_price.ToString();
textbox_item_array[3].Text = "1";
item_total = System.Convert.ToInt32(textbox_item_array[3].Text) * item.sell_price;
textbox_item_array[4].Text = item_total.ToString();
}
}
else
{
//TextBox[] textbox_item_array = new TextBox[5];
textbox_item_array = (TextBox[])(item_textbox[item_textbox.Count - 1]);
panel_item_collections.Controls.Remove(textbox_item_array[0]);

After that, it calls the same function

void dynamic_text_item_code_Leave(object sender, EventArgs e)
{
//MessageBox.Show(((Control)sender).Name.Substring(((Control)sender).Name.Length - 1, 1));
int i;
string name_textbox = ((Control)sender).Name;
i = System.Convert.ToInt32(name_textbox.Substring(name_textbox.Length - 1, 1));
//MessageBox.Show(i.ToString());
//i--;
TextBox[] textbox_item_array = new TextBox[5];
textbox_item_array = (TextBox[])(item_textbox[i]);
double item_total;
Item item = new Item();
if (long.TryParse(textbox_item_array[0].Text, out item.item_code) == true)
{
if (item.get_item() == 0)
{
textbox_item_array[1].Text = item.item_details;
textbox_item_array[2].Text = item.sell_price.ToString();
textbox_item_array[3].Text = "1";
item_total = System.Convert.ToInt32(textbox_item_array[3].Text) * item.sell_price;
textbox_item_array[4].Text = item_total.ToString();
}
}
else
{
//TextBox[] textbox_item_array = new TextBox[5];
textbox_item_array = (TextBox[])(item_textbox[item_textbox.Count - 1]);
panel_item_collections.Controls.Remove(textbox_item_array[0]);
panel_item_collections.Controls.Remove(textbox_item_array[1]);
panel_item_collections.Controls.Remove(textbox_item_array[2]);
panel_item_collections.Controls.Remove(textbox_item_array[3]);
panel_item_collections.Controls.Remove(textbox_item_array[4]);
item_textbox.RemoveAt((item_textbox.Count - 1));
row_count--;
}
}

Then it continues here

panel_item_collections.Controls.Remove(textbox_item_array[1]);
panel_item_collections.Controls.Remove(textbox_item_array[2]);
panel_item_collections.Controls.Remove(textbox_item_array[3]);
panel_item_collections.Controls.Remove(textbox_item_array[4]);
item_textbox.RemoveAt((item_textbox.Count - 1));
row_count--;
}
}

Sergey Alexandrovich Kryukov 7-Jun-13 14:57pm

Please, don't put code in comments; it's not readable. Instead, use "Improve question": click here.
—SA

2 solutions

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W∴ Balboos, *GHB* · Answer 1 · 2013-06-10T02:06:00

I have found with certain event handlers that they may be called recursively (e.g, an onchange handler that changes the item that called the event will call itself again).

I declare something like:

static bool beenHere = false;

I use it as follows

eventHandler() {

static bool beenHere = false;

 if(beenHere) {
   beenHere = false;
   return;
 }

 beenHere=true;
 /* event handler code */
 /* event handler code */
 /* event handler code */
 /* event handler code */
 return;

} // eventHandler()

adriancs · Answer 2 · 2013-06-10T15:59:00

This is not a good solution, but might prevent duplicate same events to be called.

C#

bool leaveEventIsAlreadyCalled = false;

private void SomeMethod()
{
    if (!leaveEventIsAlreadyCalled)
    {
        leaveEventIsAlreadyCalled = true; 
        // do something
    }
    else
    {
        // do nothing
    }
}

Leave Event is called more than once in C#

2 solutions

Solution 1

Solution 2

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