Develop Reference

How to find the control which causes LostMouseCapture event fire in wpf

I handled an event "LostMouseCapture" on my wpf text box . Now I need to implement functionality that if this event got fire because of click of one specific button then I want to do something and if this event got fire because of some thing else then i want to do some other thing.
I am blank how to achieve this functionality
private void txtEcode_LostMouseCapture(object sender, System.Windows.Input.MouseEventArgs e)
{
//if the event is fired because of click of "btnEcode" then do this
{
MCondsViewModel.McondsNo = MCondsViewModel.EcodeValueOnMouseFocus;
}
else
{
//do this
}
}

user control and raising events from controls placed in user control

So I would like to know what is wrong with the following code, especially from a theoretical point of view.
I have a user control in which I've added a text box.
When I click in the text box I would like the Mouse clicked event raised in the user control.
To my mind, the solution should be:
Create an event handler for the mouse click event in the text box.
in this event handler, raise the mouse click event for the user control.
so this is what i have:
private void txtLog_MouseClick(object sender, MouseEventArgs e)
{
this.OnMouseClick(e);
}
i have tried it and it doesn't work, why is this?
P.S. I would really like to know why this is wrong! A correct solution is great, but I'm really trying to understand where I'm going wrong here. Thank :-)

Well, you could just click on your textbox in design mode and in the property window in events tab add the click event. or if you want to do it in runtime you can do it like this:
textbox.Click += Txt_Click;
private static void Txt_Click(object sender, EventArgs e)
{
// do your thing
}
or even shorter:
textbox.Click += (s,e) =>
{
//do your thing
};

you should do these three steps
declare an MouseClick delegation method for textbox
assign method to textbox
add this delegation to the this (form) OnMouseClick event [on user control constructor]
Step1:
private void textBox1_MouseClick(object sender, MouseEventArgs e)
{
}
Step2:
this.textBox1.MouseClick += new System.Windows.Forms.MouseEventHandler(this.textBox1_MouseClick);
Step3:
public myUserControl()
{
InitializeComponent();
this.MouseClick += new MouseEventHandler(textBox1_MouseClick);
}

Only Keyboard event not mouse events

I have created event for KeyDown which also triggers the mouse event. I dont want the mouse event. What can i do. Here is my sample code,
private void Form1_KeyDown(object sender, KeyEventArgs e)
{
if (e.KeyCode.ToString().Equals("Up"))
{
//...
}
if (e.KeyCode.ToString().Equals("Down"))
{
//...
}
}
This works fine, but whenever i scrool the scrollbar of the mouse it triggers the respective events. What can i do now.
Thanks in advance...

How to wire up an EventHandler on a Winforms Application?

I have an application and I want to start a countdown timer.
I created an EventHandler under the partial class:
event EventHandler startTimer;
And I wrote a function:
public void startTimerEvent(object sender, EventArgs e)
{
this.Invoke((MethodInvoker)delegate
{
timer.Start();
});
}
How can I register this to the EventHandler and where do I wire it up in my form?

To tie the event to the handler:
startTimer += startTimerEvent;
But I'm not really sure there isn't a better way to go about solving your general problem. If you could describe further what you're after, perhaps we could suggest a better way.

So you need to choose an event that will trigger your handler. Let’s say you have a button, and you want to handle its click event. You could write:
myButton.Click += new EventHandler(StartWhatEver);
Then you would have your StartWhatEver that does what you want.
private void StartWhatEver(object sender, EventArgs e)
{
// Do stuff...
}
Note: If you are working in VS2010, you can type myButton.Click += (with space) then double tap the 'Tab' key and this will create your handler for you automatically including the triggered method.
Hope this helps.

Prevent multiple firing of keydown events C#

I want to allow the user to send his message when he press enter in the textbox.
I went to search and im using the sample codes below.
Now the problem is when i press enter, the event is triggered more than once like about 4-5 times.
Someone else suggested to use keyup. I have tried keyup, keydown and keypress. All have the same problem.
How do i prevent it from firing the event more than once?
private void tbxAnswer_TextChanged(object sender, EventArgs e)
{
tbxAnswer.KeyUp += new KeyEventHandler(tbxAnswer_KeyUp);
}
private void tbxAnswer_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyValue == (char)13)
{
MessageBox.Show("Hello");
}
}
Thank you!

You are adding the KeyUp event handler multiple times (inside the TextChanged handler); therefore, when Enter is pressed, the handler executes multiple times.
What you want to do here is add the KeyUp handler just once, inside your form's constructor, just after the InitializeComponent() call:
public MyForm()
{
// other code possibly here
InitializeComponent();
// and now add the event handler:
tbxAnswer.KeyUp += new KeyEventHandler(tbxAnswer_KeyUp);
}
private void tbxAnswer_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyValue == (char)13)
{
MessageBox.Show("Hello");
}
}

This is because every time you change the text, the tbxAnswer_TextChanged is called/ fired you assign an action to the keyup event; if the text is changed 4 times then you assigned the keyup event 4 times and it increases every time you change the text.
try this out:
tbxAnswer.KeyUp += new KeyEventHandler(tbxAnswer_KeyUp);
private void tbxAnswer_TextChanged(object sender, EventArgs e)
{
}
private void tbxAnswer_KeyUp(object sender, KeyEventArgs e)
{
if (e.KeyValue == (char)13)
{
MessageBox.Show("Hello");
}
}

Change your code to this
tbxAnswer.KeyUp -= tbxAnswer_KeyUp;
tbxAnswer.KeyUp += new KeyEventHandler(tbxAnswer_KeyUp);

In your code snippet, whenever the text of the TextBox changes, another eventhandler is added to the KeyUp handler. You should only add event handlers once (for instance, just after creating the textbox).

Sara and Jon have already provided the correct answer to your specific question. But if you want to go further and get a better understanding of how and when to use any particular key handling event take a look at my article Exploring Secrets of .NET Keystroke Handling. I explain and diagram when and where each event is useful, plus provide a KeystrokeSandbox application that lets you actually watch what happens!