try this
protected void lnkCompleted1_Click(object sender, EventArgs e)
{
string User1 = ((LinkButton)sender).CommandArgument;
ViewState["User1"] = User1;
MyFunction();
}
protected void MyFunction() {
strStatus = "Completedays";
grd1.Visible = true;
string User1 = ViewState["User1"]+"";
DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
}
protected void grd1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
string Eve1 = ViewState["SecondStatus"].ToString();
if (Eve1 == "Completeddays")
{
MyFunction();
}
}