Find which Linkbutton was clicked

I am giving few step to achieve the goal.

Step 1.: Define three link buttons on .aspx page but these three have same onclick event so your .aspx page is :

<div>

    <asp:LinkButton ID="LinkButton1" runat="server" onclick="LinkButton1_Click">LinkButton1</asp:LinkButton>

    <asp:LinkButton ID="LinkButton2" runat="server" onclick="LinkButton1_Click">LinkButton2</asp:LinkButton>

    <asp:LinkButton ID="LinkButton3" runat="server" onclick="LinkButton1_Click">LinkButton3</asp:LinkButton>
    </div>

Step 2: Now onclick event define on code behind page and in this event sender assign to a LinkButton that identifies which button clicked. Lets see this event

protected void LinkButton1_Click(object sender, EventArgs e)
        {
            LinkButton lnkButton = (LinkButton) sender;
            if (lnkButton.ID == "LinkButton1")
            {
                Response.Write("Button First clicked");
            }
            else if (lnkButton.ID == "LinkButton2")
            {
                Response.Write("Button second clicked");
            }
            else
            {
                Response.Write("Button third clicked");
            }
        }