Getting exception as unable to cast object of type 'asp.home_aspx' to type 'system.web.ui.webcontrols.linkbutton'.

Question

1.00/5 (1 vote)

See more:

C#

protected void grd1_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
 string Eve1 = ViewState["SecondStatus"].ToString();
if (Eve1 == "Completeddays")
{
  lnkCompleted1_Click(this, new EventArgs());
}
}

protected void lnkCompleted1_Click(object sender, EventArgs e)
{
        strStatus = "Completedays";
        grd1.Visible = true;
        User1 = ((LinkButton)sender).CommandArgument; // here i am getting error as Unable to cast object of type 'ASP.home_aspx' to type 'System.Web.UI.WebControls.LinkButton'.
        DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
}

To be more clear i have two grids one grid just displays the count of tasks and username for example and on clicking that number 
i will get second grid with paging as it has so many records and on clicking paging i need to go to the event lnkCompleted1_Click
by passing username of that particular user whom we are viewing in second grid suppose if we click radha when i click on paging of
second grid i should pass that user radha to lnkCompleted1_Click event

<pre lang="text">User                   Completed batches
nandini                                         23
geetha                                           2
radha                                            4

What I have tried:

i am getting exception as

Unable to cast object of type 'ASP.home_aspx' to type 'System.Web.UI.WebControls.LinkButton'. in tis event lnkCompleted1_Click

Posted 31-Jan-18 19:09pm

kav@94

Updated 31-Jan-18 22:55pm

v2

Add a Solution

Comments

Karthik_Mahalingam 1-Feb-18 1:29am

lnkCompleted1_Click(this, new EventArgs());
the above line doesnt make sense
"this" object will contain the instance of the current page.
how the event will know which row has clicked?

Karthik_Mahalingam 1-Feb-18 1:58am

in pagination which link you want to click?
how many rows does the grid contains in each page ?

Karthik_Mahalingam 1-Feb-18 3:55am

which DN you want to pass as CommandArgument

Karthik_Mahalingam 1-Feb-18 4:20am

so on pagination click, you need to pass the last row's id to the lnkCompleted1_Click event ?
correct?
or some other logic?

you will be clicking the page button or the link button in the grid? be more specific

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Karthik_Mahalingam · Answer 1 · 2018-01-31T22:55:00

Solution 1

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();
           }
       }

Posted 31-Jan-18 22:55pm

Karthik_Mahalingam

Updated 31-Jan-18 22:56pm

Comments

kav@94 1-Feb-18 5:00am

but i am getting error here itself know
protected void lnkCompleted1_Click(object sender, EventArgs e)
{
string User1 = ((LinkButton)sender).CommandArgument;
}

Karthik_Mahalingam 1-Feb-18 5:10am

post the markup of gridview

kav@94 1-Feb-18 5:19am

my mark ups of gridview
mark up of first griview
<asp:GridView ID="grd1" AutoGenerateColumns="false" HeaderStyle-BackColor="#708090" CssClass="EU_DataTable" PagerStyle-ForeColor="Black" HeaderStyle-ForeColor="White" runat="server" AllowPaging="true" EmptyDataText="No Records Available" Width="100%">
<columns>
<asp:BoundField HeaderText="User" DataField="DN" />
<asp:TemplateField HeaderText="New Batches">
<itemtemplate>
<asp:LinkButton ID="lnkNewBatches" OnClick="lnkNewBatches_Click" CommandName="Select" CommandArgument='<%# Eval("DN") %>' runat="server">/asp:LinkButton>

<asp:TemplateField HeaderText="Running batches"> <%-- modified working to in-progress--%>
<itemtemplate>
<asp:LinkButton ID="lnkRunningbatches" OnClick="lnkRunningbatches_Click" CommandName="Select" CommandArgument='<%# Eval("DN") %>' runat="server">

<asp:TemplateField HeaderText="CompletedBatches">
<itemtemplate>
<asp:LinkButton ID="lnkCompletedBatches" OnClick="lnkCompletedBatches_Click" CommandName="Select" CommandArgument='<%# Eval("DN") %>' runat="server">

<RowStyle ForeColor="#000066" HorizontalAlign="Center" />

mark up of second gridview

<asp:GridView ID="grd2" runat="server" ShowFooter="true" CssClass="EU_DataTable" AutoGenerateColumns="false" EmptyDataText="No Records Available"
OnPageIndexChanging="grdIndivuidualTask_PageIndexChanging" HeaderStyle-BackColor="#708090" PagerStyle-ForeColor="Black" HeaderStyle-ForeColor="White" AllowPaging="true" PageSize="2" Width="100%">
<columns>
<asp:BoundField HeaderText="Name" DataField="Name" />
<asp:BoundField HeaderText="Course" DataField="Course" />
<asp:BoundField HeaderText="Assigned To" DataField="Dn" />
<asp:BoundField HeaderText="Status" DataField="WorkStatus" />

<RowStyle ForeColor="#000066" HorizontalAlign="Center" />

Karthik_Mahalingam 1-Feb-18 5:24am

there is no lnkCompleted1_Click event in the grid

kav@94 1-Feb-18 5:26am

lnkCompletedBatches_Click is nothing but lnkCompleted1_Click both are same

Karthik_Mahalingam 1-Feb-18 5:32am

please post the complete mark up related to the gridview

kav@94 1-Feb-18 5:36am

ok do you need both gridviews code

Karthik_Mahalingam 1-Feb-18 5:42am

first grid code

kav@94 1-Feb-18 5:48am

ok sure

kav@94 1-Feb-18 5:49am

protected void lnkNewBatches_Click(object sender, EventArgs e)
{
strStatus = "NewBatches";
grd2.Visible = true;
User1 = ((LinkButton)sender).CommandArgument;
DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
if (dt.Rows.Count > 0)
{
grd2.DataSource = dt;
grd2.DataBind();
}
else
{
grd2.DataSource = null;
grd2.DataBind();
}
ViewState["SecondStatus"] = "NewBatches";
}
protected void lnkRunningbatches_Click(object sender, EventArgs e)
{
strStatus = "Runningbatches";
grd2.Visible = true;
User1 = ((LinkButton)sender).CommandArgument;
DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
if (dt.Rows.Count > 0)
{
grd2.DataSource = dt;
grd2.DataBind();
}
else
{
grd2.DataSource = null;
grd2.DataBind();
}
ViewState["SecondStatus"] = "Runningbatches";
}
protected void lnkCompletedBatches_Click(object sender, EventArgs e)
{
strStatus = "CompletedBatches";
grd2.Visible = true;
User1 = ((LinkButton)sender).CommandArgument;
DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
if (dt.Rows.Count > 0)
{
grd2.DataSource = dt;
grd2.DataBind();
}
else
{
grd2.DataSource = null;
grd2.DataBind();
}
ViewState["SecondStatus"] = "CompletedBatches";
}

Paging of second gridview

protected void grd2_PageIndexChanging(object sender, GridViewPageEventArgs e)
{
grd2.PageIndex = e.NewPageIndex;
string Eve1 = ViewState["SecondStatus"].ToString();
if (!string.IsNullOrEmpty(Eve1))
{
if (Eve1 == "CompletedBatches")
{
lnkCompletedBatches_Click(this, new EventArgs());

}
else if (Eve1 == "Runningbatches")
{
lnkRunningbatches_Click(this, new EventArgs());
}
else if (Eve1 == "NewBatches")
{
lnkNewBatches_Click(this, new EventArgs());
}
}
grd2.DataBind();
}

Karthik_Mahalingam 1-Feb-18 6:06am

try this


 protected void lnkNewBatches() {
            strStatus = "NewBatches";
            grd2.Visible = true;
            DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
            if (dt.Rows.Count > 0)
            {
                grd2.DataSource = dt;
                grd2.DataBind();
            }
            else
            {
                grd2.DataSource = null;
                grd2.DataBind();
            }
            ViewState["SecondStatus"] = "NewBatches";
        }

        protected void lnkRunningbatches() {
            strStatus = "Runningbatches";
            grd2.Visible = true;
          
            DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
            if (dt.Rows.Count > 0)
            {
                grd2.DataSource = dt;
                grd2.DataBind();
            }
            else
            {
                grd2.DataSource = null;
                grd2.DataBind();
            }
            ViewState["SecondStatus"] = "Runningbatches";
        }

        protected void lnkCompletedBatches() {
            strStatus = "CompletedBatches";
            grd2.Visible = true;
          
            DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
            if (dt.Rows.Count > 0)
            {
                grd2.DataSource = dt;
                grd2.DataBind();
            }
            else
            {
                grd2.DataSource = null;
                grd2.DataBind();
            }
            ViewState["SecondStatus"] = "CompletedBatches";
        }


        protected void lnkNewBatches_Click(object sender, EventArgs e)
        { 
            User1 = ((LinkButton)sender).CommandArgument;
            lnkNewBatches();
           
        }
        protected void lnkRunningbatches_Click(object sender, EventArgs e)
        {
            User1 = ((LinkButton)sender).CommandArgument;
            lnkRunningbatches();
        }
        protected void lnkCompletedBatches_Click(object sender, EventArgs e)
        {
            User1 = ((LinkButton)sender).CommandArgument;
            lnkCompletedBatches();
           
        }



        protected void grd2_PageIndexChanging(object sender, GridViewPageEventArgs e)
        {
            grd2.PageIndex = e.NewPageIndex;
            string Eve1 = ViewState["SecondStatus"].ToString();
            if (!string.IsNullOrEmpty(Eve1))
            {
                if (Eve1 == "CompletedBatches")
                {
                    lnkCompletedBatches();

                }
                else if (Eve1 == "Runningbatches")
                {
                    lnkRunningbatches();
                }
                else if (Eve1 == "NewBatches")
                {
                    lnkNewBatches();
                }
            }
            grd2.DataBind();
        }

kav@94 1-Feb-18 6:21am

the problem is i need to get the username of whose records we are viewing in second gridview to User1 = ((LinkButton)sender).CommandArgument; but we are not getting that

Karthik_Mahalingam 1-Feb-18 6:23am

since the user1 variable is declared outside, so there wont be any problem.

kav@94 1-Feb-18 6:26am

no user1 is coming empty we need to get the user name of the row that we are clicking in completed,new or pending batches for that particular user

Karthik_Mahalingam 1-Feb-18 6:30am

read user1 value from viewstate

  protected void lnkNewBatches() {
            strStatus = "NewBatches";
            grd2.Visible = true;
            User1 = ViewState["User1"] + "";
            DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
            if (dt.Rows.Count > 0)
            {
                grd2.DataSource = dt;
                grd2.DataBind();
            }
            else
            {
                grd2.DataSource = null;
                grd2.DataBind();
            }
            ViewState["SecondStatus"] = "NewBatches";
        }

        protected void lnkRunningbatches() {
            strStatus = "Runningbatches";
            grd2.Visible = true;
            User1 = ViewState["User1"] + "";
            DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
            if (dt.Rows.Count > 0)
            {
                grd2.DataSource = dt;
                grd2.DataBind();
            }
            else
            {
                grd2.DataSource = null;
                grd2.DataBind();
            }
            ViewState["SecondStatus"] = "Runningbatches";
        }

        protected void lnkCompletedBatches() {
            strStatus = "CompletedBatches";
            grd2.Visible = true;
            User1 = ViewState["User1"] + "";
            DataTable dt = adm.getProjectsbyStatusbyUser(strStatus, txtDate2.Text, User1);
            if (dt.Rows.Count > 0)
            {
                grd2.DataSource = dt;
                grd2.DataBind();
            }
            else
            {
                grd2.DataSource = null;
                grd2.DataBind();
            }
            ViewState["SecondStatus"] = "CompletedBatches";
        }


        protected void lnkNewBatches_Click(object sender, EventArgs e)
        { 
            User1 = ((LinkButton)sender).CommandArgument;
            ViewState["User1"] = User1;
            lnkNewBatches();
           
        }
        protected void lnkRunningbatches_Click(object sender, EventArgs e)
        {
            User1 = ((LinkButton)sender).CommandArgument;
            ViewState["User1"] = User1;
            lnkRunningbatches();
        }
        protected void lnkCompletedBatches_Click(object sender, EventArgs e)
        {
            User1 = ((LinkButton)sender).CommandArgument;
            ViewState["User1"] = User1;
            lnkCompletedBatches();
           
        }

kav@94 1-Feb-18 6:46am

there is one more small problem we are getting paging and we are able to navigate but when we are navigating that means each time when we click paging second grid is gwetting disappeared

Karthik_Mahalingam 1-Feb-18 6:55am

Check the visible property. Might have set to false somewhere

kav@94 1-Feb-18 7:29am

again in lnkCompletedBatches() usrer is becoming empty

Karthik_Mahalingam 1-Feb-18 9:39am

else ,try using session.

kav@94 1-Feb-18 5:02am

no its still not working why because i need to pass lnkCompleted1_Click(object sender, EventArgs e) in my page index changing event

Karthik_Mahalingam 1-Feb-18 5:11am

it doesn't make sense to pass this event. use some function with session or viewstate of overcome this issue.

Karthik_Mahalingam 1-Feb-18 5:25am

try

 protected void lnkCompletedBatches_Click(object sender, EventArgs e)
        {
            string  User1 = ((LinkButton)sender).CommandArgument;
            ViewState["User1"] = User1;
            MyFunction();
        }