.NET Tutorials, Forums, Interview Questions And Answers
Welcome :Guest
Sign In
Win Surprise Gifts!!!

Top 5 Contributors of the Month
Gaurav Pal
Post New Web Links

Distinguish between coding-SelectionChanged and mouse-SelectionChanged

Posted By:      Posted Date: September 11, 2010    Points: 0   Category :WPF
Distinguish between coding-SelectionChanged and mouse-SelectionChanged Hi everyone! I have a machiavellian question (for me). In my WPF application I have a ListBox that has in the ItemTemplate a Combobox. When the user select a ComboBoxItem, I have to do some complex operations on the ObservableCollection that is the ItemsSource of the ListBox, then I have to show the ListBox with the changed data. The problem is that if I handle the event "SelectionChanged" of the ComboBox control, every time I modify the source-class of the comboboxItems I enter in the method that handle the event, and this generate wrong results. In short I have to distinguish, in some way, between the SelectionChanged generated by code, and the SelectionChanged generated manually by the user with the mouse. I have tried many ways, but nothing that works :-( The soution I thought was the best, is to handle the event "GotFocus" or "MouseUp" of the ContentPresenter of the ItemContainerStyle of the Combo, or else to handle the same events ("GotFocus" and "MouseUp") of the ItemsPanel of the Combo, but the method I handled didn't capture the event (in debug the cursor doesn't enter at all in the method). I can't use a boolean to stop the method "SelectionChanged" until the "first round" is finished, because the changes of the source-clas

View Complete Post

More Related Resource Links

Combobox SelectionChanged: Prevent firing for every keystroke?

Is it possible for this event to fire only when the user clicks an item from combobox with the mouse or when they hit enter on it like the old 2.0 combobox worked? I have tried messing aroudn with the new selectionchanged event but I cannot figure it out. I looked on the forums here for help but only found someone returning the even to fire only when items they type are in the combobox. Thanks all help appreciated.GINtech Systems Owner

How to stop Datagrid SelectionChange from SelectionChanged Event



I have a DataGrid which is binded with a List. Consider I have 10 Items in the List, so in the combobox also.

Currently 2nd Item is selected in the DataGrid.

Now I am selecting the 3rd item in the DataGrid.

In the DataGrid SelectionChanged event, I am doing some validation and validation fails so I don want my Selection is changed from 2nd item to 3rd item or the selection should remain in 2nd item.

Please let me know how to do this?

In the DataGrid SelectionChanged event, I tried to set DataGrid.SelectedItem = 2ndItem.

But this didn't work properly.

Hope, my requirement is clear. If you have any doubt then please feel free to ask me.



WPF Datagrid SelectionChanged event is triggering Multiple times while loading the rows.



When i use DataGridComboBoxColumn in my WPF DataGrid, the DataGrid SelectionChanged event is triggering multiple times based on the number of rows while loading the rows in the WPF DataGrid.

How can i stop this? Because of this I am facing Performance issue.



Please remember to click "Mark as Answer" on the post that helps you, and to click "Unmark as Answer" if a marked post does not actually answer your question. This will help other members to find the solution easily.

Problem with ListView' SelectionChanged event


I have a listview (C#) with some items representing metadata objects. Near this listview I have a Panel where the structure of selected metadata object is shown.

When user selects one item I want to show my Panel (with structure of this item).

When user doesn't select any item or selects many items I want to hide my Panel.

It works but there are a lot of blinks during selection changes. I've prepared workaround to this issue by checking in SelectionChanged event whether the number of selected items changed (none -> one, one -> many, many -> one, one -> none). If the number changed so I show or hide the panel, in other cases I don't do anything.

But one blink is still here. When I just move one-item selection from one item to another then SelectionChanged occures 2 times (for previous selected item and then for next selected item). So my check works incorrectly in this case: one item selection changes to none selection (first SelectionChanged event) and panel becomes hidden, then none selection changes to one item selection (second SelectionChanged event) and panel becomes shown. So user sees blinks.

How can I detect whether user deselected all items at all or just moved the selection from one item to another.

Thanks a lot. Sorry for my English:)

Can't get SelectedDate before SelectionChanged Event @ WebControls.Calendar



I'm currently working with the View-ViewModel pattern. In addition to that I composed a base page:

public abstract class BasePage : Page
protected override void OnLoad(EventArgs e)
if (IsPostBack)

protected override void OnPreRender(EventArgs e)

protected abstract void PushLayout();
protected abstract void PullLayout();

The intention: On every page call the PullLayout() fetches all necessary data from the ViewModel object behind and updates the controls (textboxes, listboxes, etc.). After changing and submitting the the data PushLayout() writes everything back! All I have to do now is implementing these two methods for each concrete page and handle some further server control events, if any.

An example (assume ViewModel is the backend object):

public class TestPage : BasePage
protected override void PushLayout()
ViewModel.SelectedBoxItem =

protected overrid

WPF Combobox SelectionChanged with record binding


In my xaml, I have a ListBox of Customers on the left. When a customer is selected, the right will display the customer info (name, address, phone, type, etc) to a bind textbox or combobox.

On the right, the Type is a combobox that has SelectionChanged event that populate something when value is changed. The problem is whenever I select a different customer in the ListBox on the left, the Type SelectionChanged event also fire up and populate value. How can I detect and prevent this from happening? thanks!

Coding / Programming Tips for C#

Using proper guidelines and a template-framed style of coding will really helps developer to enjoy the coding with more understandable, reliable code and application development.

How to highlight datagrid or GridView row on mouse over?

This article will show how you can Ajax with GridView to display popup messages when mouse moves over certain column. In the demo project I have added first column as an image column with a help icon in it. This kind of implements a feature that if you want more information about the row you can move mouse over this icon, a asynchronous request is sent to server for data about that row and when call returns the returned message is show as a popup message.

The void is invariant

while back I described a kind of variance that we've supported since C# 2.0. When assigning a method group to a delegate type, such that both the selected method and the delegate target agree that their return type is a reference type, then the conversion is allowed to be covariant. That is, you can say:

Best Coding Techniques To Improve Performance for SharePoint Applications

As more developers write custom code by using the SharePoint Object Model, they encounter common issues that can affect application performance.

The following areas reflect the main issues encountered by developers as they write custom code by using the SharePoint object model:

§ Disposing of SharePoint objects

§ Caching data and objects

§ Writing code that is scalable

WebMatrix shorthand coding?


Will there be support for shorthand statements?


@if(1==1) @: works
@else @: doesn't work

as apposed to;

    <text>doesn't work</text>

Or perhaps ternary opperators? PHP like stuff ...

User messages without hard coding


Hi All,


How to manage user messages to avoid hardcoding messages accross the web application.





Invalid length for a Base-64 char array for my coding in ASP.net C#. How to solve it ?


Hi Friends ,

I have done encrypted password and decode but i got error  like  this  " Invalid length for a Base-64 char array" .

Pls help . Thanks


psswd = txtPassword.Text;

pwed = base64Decode(psswd);

public string base64Decode(string sData)
            System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
            System.Text.Decoder utf8Decode = encoder.GetDecoder();
            byte[] todecode_byte = Convert.FromBase64String(sData);
            int charCount = utf8Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);
            char[] decoded_char = new char[charCount];
            utf8Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);
            string result = new String(decoded_char); return result;

Better Coding: Better Coding with Visual Studio 2010


From functional IDE improvements to better support for parallel programming, Visual Studio 2010 comes with a host of new features to help meet the needs of today's demanding, ever-changing development environment. Doug Turnure provides an overview of the more important ones and practical advice on how to use them.

Doug Turnure

MSDN Magazine April 2010

Coding Tools: Improved Support For Parallelism In The Next Version Of Visual Studio


We take a look at planned support for parallel programming for both managed and native code in the next version of Visual Studio.

Stephen Toub and Hazim Shafi

MSDN Magazine October 2008

Toolbox: Realistic Test Data, Dare Obasanjo's Blog, Color-Coding Tools, and More


This month Scott shows how to generate realistic test data, visits Dare Obasanjo's blog, and demonstrates color coding code for better readability.

Scott Mitchell

MSDN Magazine October 2008

Netting C++: EEK!-Time to Design the Mouse


This month begins the design of the actual mouse class for EEK!

Stanley B. Lippman

MSDN Magazine December 2007

ASP.NetWindows Application  .NET Framework  C#  VB.Net  ADO.Net  
Sql Server  SharePoint  Silverlight  Others  All   

Hall of Fame    Twitter   Terms of Service    Privacy Policy    Contact Us    Archives   Tell A Friend