Index was out of range. Must be non-negative and less than the size of the collection. Parameter name: index

When i am click on update button i got this error
my update click event

protected void btnUpdate_Click(object sender, CommandEventArgs e)
{
    int idx = Convert.ToInt32(e.CommandArgument);
    GridViewRow gr = gvResTasks.Rows[idx];
    ...
}

when idx value is upto 19 it works fine ..when it is greater than 19 this error came..
could you please help me on this

Updatebutton.aspx

<ItemTemplate> <asp:Button runat="server" ID="btnUpdate" Text="Update" OnCommand="btnUpdate_Click" CommandArgument="<%# Container.DataItemIndex %>" /> <%--<asp:Button runat="server" ID="Button1" Text="Update" onclick="btnUpdate_Click" />--%> </ItemTemplate>

updatebutton.aspx.cs

protected void btnUpdate_Click(object sender, CommandEventArgs e)
{
   // int idx = Convert.ToInt32(e.CommandArgument);
    int idx = Convert.ToInt32(e.CommandArgument);
    GridViewRow gr = gvResTasks.Rows[idx];

    Label hf = (Label)gr.FindControl("hdEmployeeID");

    string sEmpID = hf.Text;
    lblEmployeeID.Text = sEmpID;
    lblEmployeeID2.Text = sEmpID;

    int Rows = gvResTasks.Rows.Count;
    for (int x = 0; x < Rows; x++)
    {
        GridViewRow tr = gvResTasks.Rows[x];
        tr.CssClass = "WhiteBack";
    }

    ClearMessages();

    gr.CssClass = "TealBack";

    string sSubTaskID = gr.Cells[0].Text;
    lblSubTaskID.Text = sSubTaskID;

    lblSubTaskName.Text = @gr.Cells[1].Text;

    LoadSubTaskInfo();

    Single sProgress = 0;
    Boolean bok = Single.TryParse(lblActualProgress.Text, out sProgress);




    DateTime dPF = DateTime.Parse(lblPlannedFinish.Text);

    if (dPF > DateTime.Now)
    {
        btnFinish.Enabled = false;
    }
    else if (dPF <= DateTime.Now)
    {
        if (sProgress >= 100)
        {
            btnFinish.Enabled = false;
        }
        else
        {
            btnFinish.Enabled = true;
        }
        //btnFinish.Enabled = true;
    }

    panelUpdate.CssClass = "float";
    panelUpdate.Visible = false;
    if (gr.Cells[7].Text != "True")
    {
        panelUpdate.Visible = true;
    }


}

Answers:

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Method 1

No need to use e.CommandArgument to find the GridViewRow. Just do this

GridViewRow gr = ((Button)sender).NamingContainer as GridViewRow;

Method 2

How many rows do you have?

Try this:

int idx = Convert.ToInt32(e.CommandArgument);

if (idx < gvResTasks.Rows.Count)
{
    GridViewRow gr = gvResTasks.Rows[idx];
}

Also, can you provide the btnUpdate ASPX code?

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0