Checkbox on GridView always returning False - asp.net

Question

I have a GridView with a Checkbox on the first column:
<asp:GridView ID="dgNumeradores" runat="server" AutoGenerateColumns="False" CellPadding="4" DataKeyNames="ItemID">
<Columns>
<asp:TemplateField HeaderText="Seleccionar">
<ItemTemplate>
<asp:CheckBox runat="server" ID="chkChecked" />
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField HeaderText="Item" DataField="Description">
</asp:BoundField>
<asp:BoundField HeaderText="Plantilla" DataField="Template">
</asp:BoundField>
</Columns>
</asp:GridView>
Now in the code behind I try to update the Checked column on the DataTable acting as datasource for the GridView (since, as you can see above, the Checkbox column is not bound to the datasource for reasons you probably know.):
Protected Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
Try
For Each dr As GridViewRow In Me.dgNumeradores.Rows
Me.itemsNumTable.Select("ItemID = '" & dgNumeradores.DataKeys(dr.RowIndex).Value & "'")(0)("Checked") = DirectCast(dr.Cells(0).FindControl("chkChecked"), CheckBox).Checked
Next
'Some more unimportant-for-this-question code
Catch ex As Exception
tableInfo.ShowError(ex.Message)
End Try
End Sub
The thing is that the Checkbox.Checked always returns False.
How can I get the checked state of the Checkboxes in this scenario? Or what would be the best approach into updating the aforementioned column?
P.S. Note that click on the checkboxes doesn't post back. Nothing happens on the page until the user clicks Save (and that is the intended behavior).

Answer 1

Are you binding the GridView in Page Load? If that is the case use IsPostBack
IF Not IsPostBack Then
DataBind()
End IF

Answer 2

Should you not have the AutoPostback property set to true?
<asp:CheckBox runat="server" ID="chkChecked" AutoPostback="true" />

Answer 3

I have two columns in my GridView. The first column contains filenames,
the second column contains Checkboxes. Once the user has selected an arbitrary
number of Checkboxes then by clicking a button the selected files can be
downloaded.
My markup is as follows
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:BoundField HeaderText="Available Schemas"
DataField="SchemaFileName"
SortExpression="UserId">
</asp:BoundField>
<asp:TemplateField HeaderText="Select Schema">
<ItemTemplate>
<asp:CheckBox runat="server" ID="SelectedFiles" checked= '<%# Eval("checkValue") %>'/>
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
My CodeBehind part is as follows
protected void Page_Load(object sender, EventArgs e)
{
GenerateDownloadLinks();
if (!IsPostBack)
{
GridView1.DataSource = listOfData;
GridView1.DataBind();
}
}
listOfData is populated in GenerateDownloadLinks() and then it is bind to GridView1.
Once the user selected files and clicks download then my code loops through
the rows of the GridView and when the CheckBox is checked it updates the initially
false value of the data entry to make sure which files should be made available for
download.
protected void GetFiles_Click(object sender, EventArgs e)
{
int i = 0;
foreach (GridViewRow row in GridView1.Rows)
{
CheckBox chkRow = (row.Cells[1].FindControl("SelectedFiles") as CheckBox);
if (chkRow.Checked)
{
listOfData[i].CheckValue = true;
}
i++;
}
}

Answer 4

Gridview fills perfectly even when it is not binded in Page.IsPostBack block, but here checkbox will always return false.
Bind gridview in Page.IsPostBack, and it would run perfectly fine.
Use below code
IF Not IsPostBack Then
DataBind()
End IF
And then Checkbox.Checked will return true.