How to prevent button double click from server side

Question

I made disable button on javascript button click and it works in most of cases to prevent double click,but in some cases it does not work so I want to prevent double click also from server side.

protected void Page_Load(object sender, EventArgs e)
{
   if(!IsPostBack)
  {
     hfid.value="0";
  }
}
protected void frmSubmit_Click(object sender, EventArgs e)
{
   if(Convert.ToInt32(hfid.value) == 0)
   {
   // Code of insert
   // then I set hfid.value with newly created id
   }
}

 <asp:Button ID="frmSubmitInsert" runat="server" OnClick="frmSubmit_Click" OnClientClick="GRVMasterAddButton_Click(this)" Text="Add"
                                                Width="100px" Visible="false" ValidationGroup="masterGrp" />



 function GRVMasterAddButton_Click(btn)
        {

            if (window.Page_ClientValidate('masterGrp'))
            {
             document.getElementById(btn.id).disabled = true;
                __doPostBack(btn.id, '');
            }

        }

In double click scenario,two times round trip is generated.In First round trip it is ok,but in second round trip though I am setting hfid.value with newly inserted id, it shows me 0 and again duplicate record is generated.

Not server side but you can hide button after clicking it !!! — Akash KC
– Akash KC, Commented Feb 1, 2017 at 6:06
Check out this earlier question: stackoverflow.com/questions/106509/… Answers suggest both server-side and client-side solutions — default locale
– default locale, Commented Feb 1, 2017 at 6:06
Yep, disable button after click, and enable after first operation processing is done — Sergio
– Sergio, Commented Feb 1, 2017 at 6:25
"in some cases it does not work" I am curious as to why this is the case - can you post what you did in JavaScript to disable the button when it's clicked ? — sh1rts
– sh1rts, Commented Feb 1, 2017 at 6:37

CoolBots · Accepted Answer · 2017-02-01 06:35:08Z

You can use a Session variable in your frmSubmit_Click event handler to ensure server-side that you are not running the submit code twice:

In Form_Load event, add:

Session["isProcessingForm"] = false;

Modify frmSubmit_Click event handler as follows:

protected void frmSubmit_Click(object sender, EventArgs e)
{
   if(Session["isProcessingForm"])
   {
       return;
   }

   Session["isProcessingForm"] = true;

   if(Convert.ToInt32(hfid.value) == 0)
   {
       // Code of insert
       // then I set hfid.value with newly created id
   }

   //Once form is processed
   Session["isProcessingForm"] = false;
}

If this application runs on a web farm (multiple web servers), you'll need to persist session state. There are several ways to do so in ASP.NET WebForms. More info here: https://msdn.microsoft.com/en-us/library/ms178581.aspx and here: https://msdn.microsoft.com/en-us/library/ms178587.aspx

Damith Asanka · Accepted Answer · 2017-02-01 06:30:02Z

0

Best option is disable button in client side using javascript in very first click

answered Feb 1, 2017 at 6:30

Damith Asanka

96410 silver badges12 bronze badges

2 Comments

CoolBots Over a year ago

OP is specifically asking for a server-side solution. It is stated in the question that JavaScript disabling is already in place.

Amit Bhatt Over a year ago

@CoolBots you are right,I want to prevent it from server side,I already disable it from client side.

Shiva K Thogiti · Accepted Answer · 2017-02-01 10:02:37Z

0

Try the following: It should definitely work.

    protected void Page_Load(object sender, EventArgs e)
        {
                 if(!IsPostBack)
                 {
                    hfid.value="0";
                 }
            frmSubmit.Attributes.Add("onclick", "this.disabled = true; this.value = 'Loading ...'; " + ClientScript.GetPostBackEventReference(frmSubmit, null) + ";");
        }

     protected void frmSubmit_Click(object sender, EventArgs e)
        {
            //Remove following line, this is added just to test.
            System.Threading.Thread.Sleep(5000);
            if (Convert.ToInt32(hfid.Value) == 0)
            {
                // Code of insert
                // then I set hfid.value with newly created id
            }
        }

edited Feb 1, 2017 at 10:02

answered Feb 1, 2017 at 7:02

Shiva K Thogiti

2082 silver badges6 bronze badges

5 Comments

Shiva K Thogiti Over a year ago

this will disable the button just before submitting and remain disabled until the postback is complete

CoolBots Over a year ago

Page_Load is run on every request - hfid.Value will always be set to zero in your example code. Additionally, this still relies on a client-side disabing of the button, which can take time to take effect (cost of the round-trip). The button can be clicked multiple times prior to being disabled, even if the code is corrected to persist the value and not reset it on postbacks.

Shiva K Thogiti Over a year ago

No, this will not wait for the page load to run... please try and see. From client side I am disabling the button as and when it is clicked.

CoolBots Over a year ago

Ok, that's true - you're setting that on the initial page load; it's still a client-side solution, and your hfid.Value still gets reset on every reload - basically the 2nd line in Page_Load and the if check in the frmSubmit_Click are useless code, as the if check will always return true

Shiva K Thogiti Over a year ago

Yep CoolBots, sorry. Got your point now. I was concentrating on disabling button while postback. Yes, isPostBack condition has be in place to make sure hid.Value is not overridden every time :)

Sergio · Accepted Answer · 2017-02-01 06:44:43Z

-2

You can use Lock. To prevent multiple call at same time.

private object _lockObj = new object();
protected void frmSubmit_Click(object sender, EventArgs e)
{
    // Here we lock code. When someone else will try to access to this code
    // or in your case double clicked button it will wait until _lockObj
    // is set to free.
    Lock(_lockObj)
    {
        if(Convert.ToInt32(hfid.value) == 0)
        {
        // Code of insert
        // then I set hfid.value with newly created id
        }
    }
}

edited Feb 1, 2017 at 6:44

answered Feb 1, 2017 at 6:34

Sergio

3461 silver badge8 bronze badges

7 Comments

CoolBots Over a year ago

That won't work, as the lock object will be destroyed per each request. See ASP.NET Page LifeCycle: msdn.microsoft.com/en-us/library/ms178472.aspx

sh1rts Over a year ago

This will prevent any other thread entering the locked region, which for a website is a sure-fire way to hurt scalability. Also, you're not instantiating _lockObj before use, so this will not even compile.

Sergio Over a year ago

@CoolBots It will work perfectly. The _lockObj is global @sh!rts thanks for remind. And hey, isn't he want that no one touch this part of code twice in same time? Mistakes in his logic and structure it's actually he's problem. He ask HOW TO PREVENT DOUBLE CALL (CLICK) So a believe both downvotes are not fair...

CoolBots Over a year ago

@sh1rts, actually it just won't work, even if corrected to compile - each page request instantiates a new ASP.NET Page object, which is destroyed once the request is completed - the lock object is useless.

CoolBots Over a year ago

@Sergio, the lock object is global to the class that gets created and destroyed on each request - this is web, not desktop programming! Even your comment is incorrect: "When someone else will try to access to this code or in your case double clicked button it will wait until _lockObj is set to free." - completely wrong! - a brand new instance of this Page object is created with its own lock! Unless you make it static, which would be even worse, as then only 1 user could click the button at any given time, for the entire web application!

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