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"How to Prevent multiple events C#?"

I have textbox control with auto postback = "true" in update panel and there is save button with access key of "Alt + s" when i change something into textbox and without losing focus if user has pressed "Alt + s" than need to call first text change event of textbox and then should fire save click event once as there is some calculation on text change event.In this situation first it fires text change event than it call save click event and than it calls again text change event.
Is there any good approach to resolve issue either client side or server side or from sql side?
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:TextBox ID="Txt_Val" runat="server" AutoPostBack="True"
OnTextChanged="Txt_Val_TextChanged"></asp:TextBox>
<asp:Button ID="Btn_Save" runat="server" OnClick="Btn_Save_Click"
Text="Save" AccessKey="S" ValidationGroup="S"/>
</ContentTemplate>
</asp:UpdatePanel>
protected void Btn_Save_Click(object sender, EventArgs e)
{
//Save data into database
}
protected void Txt_Val_TextChanged(object sender, EventArgs e)
{
// Some calculation
}

Solution 1 :
Here the Microsoft provide the Control.Update Method documentation here https://learn.microsoft.com/en-us/dotnet/api/system.windows.forms.control.update?view=netframework-4.8. its last update value store in Database.
Solution 2 :
please check your event its some another event call then sometimes this issue is given.
Solution 3 :
you Set focus after a update a value in the page load event
protected void Page_Load(object sender, EventArgs e)
{
TextBox1.Focus();
}
second time set focus and after update is a 3rd solution for this issue.
I hope the above three solutions is helpful.

when i change something into textbox and without losing focus if user has pressed "Alt + s" than need to call first text change event of textbox and then should fire save click event once as there is some calculation on text change event
quoted statement can also be handled like this:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:TextBox ID="Txt_Val" runat="server" AutoPostBack="True"
OnTextChanged="Txt_Val_TextChanged"></asp:TextBox>
<asp:Button ID="Btn_Save" runat="server" OnClick="Btn_Save_Click"
Text="Save" AccessKey="S" ValidationGroup="S" OnClientClick="return verifyFirst();" />
</ContentTemplate>
</asp:UpdatePanel>
<script>
function verifyFirst(){
return verifyChangedText($('[id$=Txt_Val]'));
}
function verifyChangedText(elem){
//verify your stuff on client level.
//if you need to do the server side stuff, hit WebMethod using ajax
//finally according to the result
if(everythingIsOk){
return true;
}
return false;
}
</script>
onClientClick executes first on client side, if everything is satisfactory the return bool value if true it executes the server side event call OnClick="Btn_Save_Click" and if its false then it doesn't execute the server side event call.
UPDATED
I have multiple textboxes with text change event on page or in grid for each text box control it will be difficult to handle
as per your comment quoted above, you can handle multiple TextBox verification
but it can only be handled in following manner:
if a user presses enter without focusing out then we don't know on which TextBox user made changes to so we will have to check all the TextBoxes present in the form and fire each TextBox's onkeypress event.
for e.g:
i = 0;
function verifyMe(event,args){
debugger;
$(args).text(i += 1);
};
function verifyThisStuff(){
var e = jQuery.Event("keypress");
$('.forVerification').each(function(){
$(this).trigger(e);
});
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<input type="text" class="forVerification" onkeypress="return verifyMe(event,'#span1');">
<input type="text" class="forVerification" onkeypress="return verifyMe(event,'#span2');">
<button type="button" onclick="return verifyThisStuff();">click Me</button>
<p>textbox 1 Keypresses: <span id="span1">0</span></p>
<p>textbox 2 Keypresses: <span id="span2">0</span></p>

How to implement a click event on textbox in ASP.NET?

In my web application I need a functionality so that when users click on textbox to input values, it should make the button and the other fields visible?
I am using the code provided below but, could not get it working.
C#:
protected void TextBox1_Click(object sender, EventArgs e)
{
ButtonSearch.Visible = true;
}
ASP.NET:
<asp:TextBox ID="TextBox1" runat="server" OnTextChanged="TextBox1_TextChanged" OnClick="TextBox1_Click"></asp:TextBox>
<asp:Button ID="ButtonSearch" runat="server" OnClick="ButtonSearch_Click" Text="Search" Visible="False" />
How to accomplish this?

Set AutoPostback="True". This way the event will be fired server-side, and the button will become visible.
<asp:TextBox ID="TextBox1" runat="server" OnTextChanged="TextBox1_TextChanged" OnClick="TextBox1_Click" AutoPostBack="true"></asp:TextBox>
However, if you only want to toogle visility of a button, you really should considerate javascript. This will save a trip back to the server.
<asp:TextBox onclick="txtBox1_ClientClicked()" ID="TextBox1" runat="server" OnClick="TextBox1_Click"></asp:TextBox>
<asp:Button ID="ButtonSearch" runat="server" OnClick="ButtonSearch_Click" Text="Search" style="display:none;" />
<script type="text/javascript">
function txtBox1_ClientClicked(){
var theButton = document.getElementById('<%=ButtonSearch.ClientID%>');
theButton.style.display = 'block';
}
</script>

You do not need to post back to the server to accomplish your job. You can use client side onFocus event and javascript/jquery, for example.
I know I used an input of type text, and you are using an ASP Control which posts on server, but here is a JSFiddle to get you on the right track: http://jsfiddle.net/Mmjtz/1/

$("<%= ButtonSearch.ClientID %>").click(function(){
$("#TextBox1").show():
});
In this code you need to pass fields ID which you want to visible on the click of button.

Put the textbox inside a div and use the div's onClick event from codebehind. It's not what you asked but it works for me without any errors. Here is a javascript function to implement requested event:
function toggleVisibility()
{
document.getElementById('TextBox1').disabled = true;
/*
...some other code...
*/
}
And of course, you have to define your onclick event at the div definition after implementing this JS function.
<div id="TBdiv" onClick="toggleVisibility()">
<asp:TextBox ID="TextBox1"..../>
</div>
IMPORTANT: Since you now disabled your TextBox from codebehind, you have to enable it in somewhere before you want to use it again. Otherwise you will not see it while the page is running.

jQuery is the perfect solution for your problem. The code would be something like this:
$("#TextBox1").on("click",function(){$("#ButtonSearch").css("visibility", "visible");})
You include the script by adding <script src="//ajax.googleapis.com/ajax/libs/jquery/1.11.0/jquery.min.js"></script> to the page and then you can add the piece of code above to within <script></script> tags.

How to check whether ASP.NET button is clicked or not on page load

How can I check whether a particular button was clicked or not in ASP.NET?
I think I need to perform some operation on Page_Load. This shouldn't be entering to Button_Click event to find. Is there any way that I can find where it was clicked or not on Client Side and take it to Page_Load?

Background: Basically __EVENTTARGET and __EVENTARGUMENT , These two Hidden controls are added to the HTML source, when ever any autopostback attribute is set to true for any of the web control.
The __EVENTTARGET hidden variable will tell the server ,which control actually does the server side event firing so that the framework can fire the server side event for that control.
The __ EVENTARGUMENT variable is used to provide additional event information if needed by the application, which can be accessed in the server.
So we can easily get the control causing postback using:Request.Params.Get("__EVENTTARGET");
PROBLEM:
The method: Request.Params.Get("__EVENTTARGET"); will work for CheckBoxes, DropDownLists, LinkButtons, etc.. but this does not work for Button controls such as Buttons and ImageButtons
The Button controls and ImageButton controls does not call the __doPostBack function. Because of this, the _EVENTTARGET will always be empty. However, other controls uses javascript function __doPostBack to trigger postback.
So, I will suggest to do something as below. Add an OnClientClick property to the buttons. Also, define a hiddenField in your Markup, whose value will contain the actual button causing postback.
<asp:Button ID="Button1" runat="server" Text="Button"
OnClientClick = "SetSource(this.id)" />
<asp:ImageButton ID="ImageButton1" runat="server"
OnClientClick = "SetSource(this.id)" />
<asp:HiddenField ID="hidSourceID" runat="server" />
On the OnClientClick property of the Button and ImageButton Call the SetSource JavaScript function
<script type = "text/javascript">
function SetSource(SourceID)
{
var hidSourceID =
document.getElementById("<%=hidSourceID.ClientID%>");
hidSourceID.value = SourceID;
}
</script>
Here onwards, you can very easily check in your Page_Load as to which Control caused postback:
if (IsPostBack)
{
string CtrlName;
CtrlName=hidSourceID.Value;
}

I just got the same trouble, have to do some logic judgement in the Page_Load method to treat different event(which button was clicked).
I realize the arm to get the as the following example.
The front end aspx source code(I have many Buttons with IDs F2, F3, F6, F12.
<Button Style="display: none" ID="F2" runat="server" Text="F2:Cancel" OnClientClick="SeiGyo(this)" OnClick="F2_Click" />
<Button Style="display: none" ID="F3" runat="server" Text="F3:Return" OnClientClick="SeiGyo(this)" OnClick="F3_Click" />
<Button Style="display: none" ID="F6" runat="server" Text="F6:Run" OnClientClick="SeiGyo(this)" OnClick="F6_Click" />
<Button Style="display: none" ID="F12" runat="server" Text="F12:Finish" OnClientClick="SeiGyo(this)" OnClick="F12_Click" />
The back end aspx.cs source code, what I need to do is judge which button was clicked when Page_Load was triggered. It seems a little stupid, but works.
In your situation, the button be clicked will be added into dic. I hope that will be helpful to some one.
Dictionary<string, string> dic = new Dictionary<string, string>();
foreach(var id in new string[]{"F2","F3","F6","F12"})
{
foreach (var key in Request.Params.AllKeys)
{
if (key != null && key.ToString().Contains(id))
dic.Add(id, Request[key.ToString()].ToString());
}
}

The UniqueID of the button will be in Request.Form["__EVENTTARGET"]
This question is already answered at: ASP.NET : Check for click event in page_load

You can try using the hidden field. Make the client side event on the OnclientClick event and try setting the value of hidden field, may be true or false depending on the condition.
And on the page load you can check the value of Hiidden field.
function click()
{
// set the hidden field here
}
And on the page load, simply check the value.
if(HiddenFieldName.Value=="true")
{
//perform the action
}

private bool button1WasClicked = false;
private void button1_Click(object sender, EventArgs e)
{
button1WasClicked = true;
}
if ( button1WasClicked== false)
{
//do somthing
}

Setting a session variable before AutoPostBack fires in an asp:Button

How would I go about setting a session variable from the click of an ASP:Button before an AutoPostBack event fires.
Here is what I have right now, but I'm not exactly sure I'm doing this right:
<asp:Button ID="CommitBTN" runat="server" PostBackUrl="~/MMR_Home.aspx"
onclick="CommitBTN_Click" UseSubmitBehavior="true"
OnClientClick='<% string temp1 = "true"; Session["ClickedFlag"] = temp1; %>' Text="Commit Changes to Database" />
Would this be the correct way of performing this action or am I going at it completely wrong?
EDIT:
Changed my button tag to this:
<asp:Button ID="CommitBTN" runat="server" PostBackUrl="~/MMR_Home.aspx"
onclick="CommitBTN_Click" OnClientClick="document.getElementById('<%= Hidden.ClientID
%>').value='1'" UseSubmitBehavior="true" Text="Commit Changes to Database" />
I receive this as my error:
Microsoft JScript runtime error: Unable to set value of the property 'value': object is null or undefined

Use this:
Inside aspx file:
<form runat="server">
<asp:Button ID="CommitBTN" runat="server" Text="Button" onclick="CommitBTN_Click" OnClientClick="document.getElementById('HiddenField').value='Ram'"/>
<asp:HiddenField ID="HiddenField" runat="server" />
</form>
Or
<script type="text/javascript">
function setMyHiddenField(myValue) {
document.getElementById('HiddenField').value = myValue;
}
</script>
<form runat="server">
<asp:Button ID="CommitBTN" runat="server" Text="Button" onclick="CommitBTN_Click" OnClientClick="setMyHiddenField('Ram')"/>
<asp:HiddenField ID="HiddenField" runat="server" />
==================================================================
Inside aspx.cs file
protected void CommitBTN_Click(object sender, EventArgs e)
{
Session["ClickedFlag"] = HiddenField.Value;
Response.Write(Session["ClickedFlag"]);
}
It is easy to replase "Ram" with your value. ;)
you can change Ram to temp1 easy:
setMyHiddenField('temp1')
Or you can call this function on your another control events befor CommitBTN pressed

Use a Hidden Field control.
Update the Hidden Field to 1 on Button Client Click.
Update the Session Value in the Page Load' event. The Value will be 1 then update the Session variable and set theHidden Fieldvalue to 0 underneath theSession Variable` Update.
Reason for the Usage of Page Load event is that on clicking the Button as per the page life cycle the page events like PreInit, Init, InitComplete, PreLoad, Load executes before the execution of Button Control.
Page events execution takes place like below..
Preinit
Init
InitComplete
PreLoad
Load
Control Event
Load Complete
Pre Render
Hope this will help you...

How to make the button_Click event opens the page in a pop-up window in ASP.NET?

The question is simple but I can't find a simple answer to it! .. btw I'll need to pass a QueryString to the page to be open.
Any ideas ?

You can actually link a javascript code into .NET with C#, below is an example, you could replace with your info, and push the parameters.
Response.Write("<script type='text/javascript'>window.open('Page.aspx?ID=" + YourTextField.Text.ToString() + "','_blank');</script>");
You can append on the end of it ?Field=your value passing&nextField=another value.

Is the answer to do this in javascript. As you make the underlying page in asp.net, provide it with the javascript to catch the buttons onclick event and call window.open(URL)

It depends on what you're trying to do but the simplest is to use the OnClientClick property of the Button. Take a look at http://msdn.microsoft.com/en-us/library/7ytf5t7k.aspx, in particular the details bout this property a little bit down.
Basically you'd do something like
<asp:Button ID="Button1" Runat="server"
OnClientClick="ShowPopup();"
Text="Test Client Click" />
With the JS to do your popup
<script type="text/javascript">
function ShowPopup() {
window.open('ThankYou.aspx');
}
</script>
You can also do both an OnClientClick and an OnClick if you need as well.
<asp:Button ID="Button1" Runat="server"
OnClick="Button1_Click"
OnClientClick="ShowPopup();"
Text="Test Client Click" />
Code behind
protected void Button1_Click(Object sender, EventArgs e)
{
Label1.Text = "Server click handler called.";
}