How to find out the private field value of the TextBox Leave event?
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Based on this question I am trying to do the same thing for the TextBox Leave event. This should have been a no-brainer and I created an extension method as follows:
public static class TextBoxExtensions
{
public static bool IsLeaveEventWired(this TextBox txt)
{
var eventKey = typeof(TextBox).GetField("EVENT_LEAVE",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Static)
.GetValue(txt);
EventHandlerList eventList = typeof(TextBox).GetProperty("Events",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Instance)
.GetValue(txt, null) as EventHandlerList;
return eventList[eventKey] != null;
}
}
The problem is that apparently the EVENT_LEAVE key does not exist because I am getting a NullReferenceException. So far I have tried getting all the TextBox's fields but I only get one FieldInfo object "EVENT_TEXTALIGNCHANGED" which is not an event that I have a handler for and the two events that I do, "Leave" and "KeyUp" are not included in the list.
So as the title of the question, how can I find the key to the TextBox's Leave event to see if it is wired or not?
Thank you.
c# winforms events
asked Nov 8 at 21:37
Sergio Romero
2,68772954
add a comment |
up vote
0
down vote
favorite
Based on this question I am trying to do the same thing for the TextBox Leave event. This should have been a no-brainer and I created an extension method as follows:
public static class TextBoxExtensions
{
public static bool IsLeaveEventWired(this TextBox txt)
{
var eventKey = typeof(TextBox).GetField("EVENT_LEAVE",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Static)
.GetValue(txt);
EventHandlerList eventList = typeof(TextBox).GetProperty("Events",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Instance)
.GetValue(txt, null) as EventHandlerList;
return eventList[eventKey] != null;
}
}
The problem is that apparently the EVENT_LEAVE key does not exist because I am getting a NullReferenceException. So far I have tried getting all the TextBox's fields but I only get one FieldInfo object "EVENT_TEXTALIGNCHANGED" which is not an event that I have a handler for and the two events that I do, "Leave" and "KeyUp" are not included in the list.
So as the title of the question, how can I find the key to the TextBox's Leave event to see if it is wired or not?
Thank you.
c# winforms events
asked Nov 8 at 21:37
Sergio Romero
2,68772954
@RufusL - It did not work. I have tried this exact same code from the original post with a ComboBox and it does work as is. the issue here is to figure out the Leave event key. I suppose.
– Sergio Romero
Nov 8 at 21:53
Well when I dotypeof(TextBox).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static), it returns only a single item, namedEVENT_TEXTALIGNCHANGED, so it seems like something else is needed.
– Rufus L
Nov 8 at 22:12
How to check which event are assigned?. Determine list of event handlers bound to event.
– Jimi
Nov 9 at 1:50
But, if you're looking for a way to keep track of what event are assigned to a Control/Class or verify whether a Component has already an event handler attached to an event, you could consider a class that is delegated to this task from the beginning. See the examples on: How to: Handle Multiple Events Using Event Properties and the EventHandlerList Class.
– Jimi
Nov 9 at 1:51
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
Based on this question I am trying to do the same thing for the TextBox Leave event. This should have been a no-brainer and I created an extension method as follows:
public static class TextBoxExtensions
{
public static bool IsLeaveEventWired(this TextBox txt)
{
var eventKey = typeof(TextBox).GetField("EVENT_LEAVE",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Static)
.GetValue(txt);
EventHandlerList eventList = typeof(TextBox).GetProperty("Events",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Instance)
.GetValue(txt, null) as EventHandlerList;
return eventList[eventKey] != null;
}
}
The problem is that apparently the EVENT_LEAVE key does not exist because I am getting a NullReferenceException. So far I have tried getting all the TextBox's fields but I only get one FieldInfo object "EVENT_TEXTALIGNCHANGED" which is not an event that I have a handler for and the two events that I do, "Leave" and "KeyUp" are not included in the list.
So as the title of the question, how can I find the key to the TextBox's Leave event to see if it is wired or not?
Thank you.
c# winforms events
asked Nov 8 at 21:37
Sergio Romero
2,68772954
Based on this question I am trying to do the same thing for the TextBox Leave event. This should have been a no-brainer and I created an extension method as follows:
public static class TextBoxExtensions
{
public static bool IsLeaveEventWired(this TextBox txt)
{
var eventKey = typeof(TextBox).GetField("EVENT_LEAVE",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Static)
.GetValue(txt);
EventHandlerList eventList = typeof(TextBox).GetProperty("Events",
System.Reflection.BindingFlags.NonPublic |
System.Reflection.BindingFlags.Instance)
.GetValue(txt, null) as EventHandlerList;
return eventList[eventKey] != null;
}
}
The problem is that apparently the EVENT_LEAVE key does not exist because I am getting a NullReferenceException. So far I have tried getting all the TextBox's fields but I only get one FieldInfo object "EVENT_TEXTALIGNCHANGED" which is not an event that I have a handler for and the two events that I do, "Leave" and "KeyUp" are not included in the list.
So as the title of the question, how can I find the key to the TextBox's Leave event to see if it is wired or not?
Thank you.
c# winforms events
c# winforms events
asked Nov 8 at 21:37
Sergio Romero
2,68772954
asked Nov 8 at 21:37
Sergio Romero
2,68772954
asked Nov 8 at 21:37
Sergio Romero
2,68772954
asked Nov 8 at 21:37
Sergio Romero
2,68772954
asked Nov 8 at 21:37
Sergio Romero
2,68772954
2,68772954
@RufusL - It did not work. I have tried this exact same code from the original post with a ComboBox and it does work as is. the issue here is to figure out the Leave event key. I suppose.
– Sergio Romero
Nov 8 at 21:53
Well when I dotypeof(TextBox).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static), it returns only a single item, namedEVENT_TEXTALIGNCHANGED, so it seems like something else is needed.
– Rufus L
Nov 8 at 22:12
How to check which event are assigned?. Determine list of event handlers bound to event.
– Jimi
Nov 9 at 1:50
But, if you're looking for a way to keep track of what event are assigned to a Control/Class or verify whether a Component has already an event handler attached to an event, you could consider a class that is delegated to this task from the beginning. See the examples on: How to: Handle Multiple Events Using Event Properties and the EventHandlerList Class.
– Jimi
Nov 9 at 1:51
add a comment |
@RufusL - It did not work. I have tried this exact same code from the original post with a ComboBox and it does work as is. the issue here is to figure out the Leave event key. I suppose.
– Sergio Romero
Nov 8 at 21:53
Well when I dotypeof(TextBox).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static), it returns only a single item, namedEVENT_TEXTALIGNCHANGED, so it seems like something else is needed.
– Rufus L
Nov 8 at 22:12
How to check which event are assigned?. Determine list of event handlers bound to event.
– Jimi
Nov 9 at 1:50
But, if you're looking for a way to keep track of what event are assigned to a Control/Class or verify whether a Component has already an event handler attached to an event, you could consider a class that is delegated to this task from the beginning. See the examples on: How to: Handle Multiple Events Using Event Properties and the EventHandlerList Class.
– Jimi
Nov 9 at 1:51
@RufusL - It did not work. I have tried this exact same code from the original post with a ComboBox and it does work as is. the issue here is to figure out the Leave event key. I suppose.
– Sergio Romero
Nov 8 at 21:53
@RufusL - It did not work. I have tried this exact same code from the original post with a ComboBox and it does work as is. the issue here is to figure out the Leave event key. I suppose.
– Sergio Romero
Nov 8 at 21:53
Well when I do
typeof(TextBox).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static), it returns only a single item, named EVENT_TEXTALIGNCHANGED, so it seems like something else is needed.– Rufus L
Nov 8 at 22:12
Well when I do
typeof(TextBox).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static), it returns only a single item, named EVENT_TEXTALIGNCHANGED, so it seems like something else is needed.– Rufus L
Nov 8 at 22:12
How to check which event are assigned?. Determine list of event handlers bound to event.
– Jimi
Nov 9 at 1:50
How to check which event are assigned?. Determine list of event handlers bound to event.
– Jimi
Nov 9 at 1:50
But, if you're looking for a way to keep track of what event are assigned to a Control/Class or verify whether a Component has already an event handler attached to an event, you could consider a class that is delegated to this task from the beginning. See the examples on: How to: Handle Multiple Events Using Event Properties and the EventHandlerList Class.
– Jimi
Nov 9 at 1:51
But, if you're looking for a way to keep track of what event are assigned to a Control/Class or verify whether a Component has already an event handler attached to an event, you could consider a class that is delegated to this task from the beginning. See the examples on: How to: Handle Multiple Events Using Event Properties and the EventHandlerList Class.
– Jimi
Nov 9 at 1:51
add a comment |
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@RufusL - It did not work. I have tried this exact same code from the original post with a ComboBox and it does work as is. the issue here is to figure out the Leave event key. I suppose.
– Sergio Romero
Nov 8 at 21:53
Well when I do
typeof(TextBox).GetFields(System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Static), it returns only a single item, namedEVENT_TEXTALIGNCHANGED, so it seems like something else is needed.– Rufus L
Nov 8 at 22:12
How to check which event are assigned?. Determine list of event handlers bound to event.
– Jimi
Nov 9 at 1:50
But, if you're looking for a way to keep track of what event are assigned to a Control/Class or verify whether a Component has already an event handler attached to an event, you could consider a class that is delegated to this task from the beginning. See the examples on: How to: Handle Multiple Events Using Event Properties and the EventHandlerList Class.
– Jimi
Nov 9 at 1:51