I have a DataGrid and a DataPager bound to a DomainDataSource. That part works fine. The problem is, I have a function to handle double clicking on a DataGridRow
private void dataGrid_list_LoadingRow(object sender, DataGridRowEventArgs e)
{
e.Row.AddHandler(Control.MouseLeftButtonDownEvent, new MouseButtonEventHandler(Row_MouseLeftButtonDown), true);
}
The actual logic of Row_MouseLeftButtonDown isn't important. It works fine, except for once I've clicked to another page using the DataPager. Now I'm showing that I've got two Mouse Clicks firing at the same time (which is triggering my double click when it shouldn't). If I click through four pages, I register FIVE clicks when I click on a row (one for the row click, and I guess one for each time I clicked to change pages with the DataPager)
Any idea why this is happening and how I can fix it? I tried putting a random button on the page that doesn't do anything, and clicking that doesn't cause this problem, so it doesn't seem to be just any click.
The event is being registered each time dataGrid_list_LoadingRow is called which must be happening whenever you click to another page.
private void dataGrid_list_LoadingRow(object sender, DataGridRowEventArgs e)
{
e.Row.RemoveHandler(Control.MouseLeftButtonDownEvent, Row_MouseLeftButtonDown);
e.Row.AddHandler(Control.MouseLeftButtonDownEvent, Row_MouseLeftButtonDown, true);
}
On the first time this is hit, RemoveHandler will not cause any problems as it will simply have no effect, according to the documentation. But on the second time this function is hit, it will remove the initially registered handler and simply add it again. This way, you won't just keep building up the list of registered handlers.
Also, new MouseButtonEventHandler(Row_MouseLeftButtonDown) is not necessary, you can just use Row_MouseLeftButtonDown (see Add/Remove handler to textbox).
Related
I am trying to use the MouseClick event from the properties of a listView to handle left and right mouse clicks.
Unfortunately the event never seems to fire. (Double clicked on the event to create a property, entered a bit of simple code and placed a breakpoint on the first line). The same is true of several other events listed in the properties (ItemSelectionChanged seems to work but the other events I have tried don't fire.
Here is the code added:
In form.designer.cs:
this.listView1.MouseClick += new System.Windows.Forms.MouseEventHandler(this.listView1_MouseClick);
In form.cs:
private void listView1_MouseClick(object sender, MouseEventArgs e)
{
Some code
}
That method never gets called when I click on the listview. The listview is inside a tab on top of the stack.
I guess I am probably forgetting something very basic but what?
ListView is a bit unusual, its MouseClick event doesn't fire unless you click an item in the view. Workaround is to use the MouseDown or MouseUp event instead. You typically are much more interested in the ItemSelectionChanged event btw. You probably need its HitTest() method to see exactly what was clicked if you use MouseDown/Up.
I am having a strange problem with the .NET TabControl in C# (Visual Studio 2010). Start a Windows Forms Application. Add a tab control and a button. Add two different labels to the two tab pages so you can differentiate them. The purpose of the button is just to act as a next button; subscribe to the its Click event with the code:
tabControl1.SelectTab(1);
Let's assume the user entered something wrong on the first tab, so when they try to go to the second tab we want to send them back, so subscribe to the tab control's SelectedIndexChanged event with the code:
if(tabControl1.SelectedIndex == 1)
{
tabControl1.SelectTab(0);
}
Now run the program and click the button. You will notice that as judged by the highlighted tab at the top, the first tab page is the one that appears to be selected, as you'd expect. However, as judged by the tab page that actually appears in the body of the tab control, it's still the second tab page that shows up! Calls to various controls' Focus(), Update(), and Refresh() functions don't seem to help. What is going on here?
I repro. This is a generic problem with event handlers, you can confuse the stuffing out the native Windows control by jerking the floor mat like that. TreeView is another control that's very prone to this kind of trouble.
There's an elegant and general solution for a problem like this, you can use Control.BeginInvoke() to delay the command. It will execute later after the native control is done with the event generation and all side-effects have been completed. Which solves this problem as well, like this:
private void tabControl1_SelectedIndexChanged(object sender, EventArgs e) {
if (tabControl1.SelectedIndex == 1) {
this.BeginInvoke(new Action(() => tabControl1.SelectTab(0)));
}
}
I was wonder how can I fire an event when the user double click on my webbrowser component. Since it has no such event how it could be possible...
Thanks in advance
Sounds like a WPF matter :-)
There you would go with an Behaviour attached to the browser. See this link for more information about this approach if you can alter your application (dependends on what you have done yet).
If you can't apply this solution, just bind a event handler to the click event and count click per time with respect to the mouse movement since the last click and if both conditions are true (two clicks in 0.2 secs, mouse hasn't moved more than 2px, for example) execute your double click code. The events you should use are previewMOUSEdown or MOUSEdown, not KEYdown.
// Call this where you want to create the event (let's say on the form load for example).
webBrowser1.DoubleClick += new EventHandler(webBrowser1_DoubleClick);
// This happens when the event is fired (so when you double click on the webbrowser control).
void webBrowser1_DoubleClick(object sender, EventArgs e)
{
// Code
}
Try this.
I don't know why you can't set this event via the designer :(, but this should work.
I have a control which is a button and I want to manually click it. (When the user presses a button)
I have the control but I don't know how to get it's function. (The format of the click function is [Control.Name]_Click(object sender, EventArgs e) as usual
Does anyone know how to do this?
If you have the button, instead of trying to find the method, I would recommend just calling Button.PerformClick instead. This will trigger all of the event handlers on the button's Click event, no matter what name they've been assigned.
I am pasting text in textbox1.text and I need textbox1 should fire its leave event by itself.
For now I am using this following code. but i will appreciate if anyone can suggest me an elegant or better way:-
private void event()
{
textbox1.Text = SearchedText;
textbox1.Focus();
textbox2.Focus();
}
First I am pasting text, then setting up Focus on the control, then set up focus again on second control. It is firing leave event of textbox1, but any thing better?
Just call the code directly, no need to wait for an event:
private void textBox1_Leave(object sender, EventArgs e) {
mumble();
}
private void someEvent() {
textBox1.Text = SearchedText;
mumble();
}
void mumble() {
// etc...
}
Just calling textBox1_Leave(this, EventArgs.Empty) works fine too.
You should handle the TextChanged or Validated events instead of the Leave event.
To FORCE Leave, Validating and so on Events, no matter what, I've found ONE working solution.
First i tried:
ProcessTabStop(true);
ProcessTabStop(false);
instead of:
textbox1.Focus();
textbox2.Focus();
Problem with the TextBox 1 and 2 Focus() is that its only Active Component that needs Leave, Validating and so on fired, not other Controls, and besides, what if the form is dynamic, you as a programmer not necessarily have any idea what Control you are trying to Leave, that's why i changed Control.Focus() method to ProcessTabStop method above. The problem is then, if only ONE Control has TabStop true, there is no control to go to and back from. So Events are NOT Fired.
Next problem is that i not necessarily Close the Form with the mouse so Focus doesn't change, I use a Key (Ctrl+Enter) to Accept the Form, and then Leave, validating and so on are NOT fired, when i Send Form Close, as Form Close registers weather there are changes or not. But Values are set in Leave on TextBoxes, so I had to find a solution that worked no matter what i did to it. I almost gave up, actually i had a problem report all filled out, when I thought, what if i set ActiveControl to Null and then to the Control it came from. It worked, but had som "Flicker" due to color change on Parent Panel depending on Active or Inactive.
The "Workaround" that works in all cases is:
Control Old = ActiveControl;
// ActiveControl.SuspendLayout();
// ActiveControl.FindForm().SuspendLayout();
ActiveControl = null;
ActiveControl = Old;
// ActiveControl.FindForm().ResumeLayout();
// ActiveControl.ResumeLayout();
That seems to fire Leave, Validating and so on Events, no matter number of Form Controls and TabStopped Controls. You MAY need to SuspendLayout on either ActiveControl, or Form. My Control (Parent Panel) changes color when Active/Inactive, if I do not Suspend Layout on Form, parent panel gets an unwanted "flicker" effect.
Looking at the solution, it is very obvious, now I've found it, but took me half a day to try different things that solved one or another problem, but not all.
I know this a VERY old thread, but one of very few articles I've found on the subject of Forcing Leave Event to be Fired.