On postback how can I check which control cause postback in Page Init event

Question

On postback  how can I check which control cause postback in Page Init event    protected void Page Init object sender  EventArgs e      need to check here which control cause postback       Thanks

User · Answer

To get exact name of control  use       string controlName   Page FindControl Page Request Params    EVENTTARGET    ID

User · Answer

if  Request Params    EVENTTARGET      null      if  Request Params    EVENTTARGET   ToString   Contains  myControlID            DoWhateverYouWant

User · Answer

Either directly in form parameters or  string controlName   this Request Params Get    EVENTTARGET      Edit  To check if a control caused a postback  manually       input Image with name  imageName  if  this Request  imageName    x      null        caused postBack     Other input with name  name  if  this Request  name      null        caused postBack   You could also iterate through all the controls and check if one of them caused a postBack using the above code

User · Answer

I see that there is already some great advice and methods suggest for how to get the post back control  However I found another web page  Mahesh blog  with a method to retrieve post back control ID   I will post it here with a little modification  including making it an extension class  Hopefully it is more useful in that way        lt summary gt      Gets the ID of the post back control           See  http   geekswithblogs net mahesh archive 2006 06 27 83264 aspx      lt  summary gt       lt param name    page  gt The page  lt  param gt       lt returns gt  lt  returns gt  public static string GetPostBackControlId this Page page        if   page IsPostBack          return string Empty       Control control   null         first we will check the    EVENTTARGET  because if post back made by the controls        which used   doPostBack  function also available in Request Form collection      string controlName   page Request Params    EVENTTARGET        if   String IsNullOrEmpty controlName                 control   page FindControl controlName             else                  if   EVENTTARGET is null  the control is a button type and we need to            iterate over the form collection to find it             ReSharper disable TooWideLocalVariableScope         string controlId          Control foundControl             ReSharper restore TooWideLocalVariableScope          foreach  string ctl in page Request Form                           handle ImageButton they having an additional  quasi-property                  in their Id which identifies mouse x and y coordinates             if  ctl EndsWith   x      ctl EndsWith   y                                  controlId   ctl Substring 0  ctl Length - 2                   foundControl   page FindControl controlId                             else                               foundControl   page FindControl ctl                              if    foundControl is IButtonControl   continue               control   foundControl              break                       return control    null   String Empty   control ID      Update  2016-07-22   Type check for Button and ImageButton changed to look for IButtonControl to allow postbacks from third party controls to be recognized

User · Answer

Assuming it s a server control  you can use     Request  ButtonName    To see if a specific button was clicked  if  Request  ButtonName      null

User · Answer

An addition to previous answers  to use Request Params    EVENTTARGET   you have to set the option   buttonName UseSubmitBehavior   false

User · Answer

Here s some code that might do the trick for you  taken from Ryan Farley s blog   public static Control GetPostBackControl Page page        Control control   null       string ctrlname   page Request Params Get    EVENTTARGET        if  ctrlname    null  amp  amp  ctrlname    string Empty                control   page FindControl ctrlname             else               foreach  string ctl in page Request Form                        Control c   page FindControl ctl               if  c is System Web UI WebControls Button                                control   c                  break                                    return control

User · Answer

If you need to check which control caused the postback  then you could just directly compare     EVENTTARGET   to the control you are interested in   if  specialControl UniqueID    Page Request Params    EVENTTARGET            do special stuff       This assumes you re just going to be comparing the result from any GetPostBackControl      extension method anyway  It may not handle EVERY situation  but if it works it is simpler  Plus  you won t scour the page looking for a control you didn t care about to begin with

[c#] On postback, how can I check which control cause postback in Page_Init event

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