Problem extracting checkbox checked status from GridView

Question

User615288127 posted

I'm using Visual Studio 2015 and SQL Server 2014, VB.

I have a Gridview where the first two columns are checkboxes.  In the routine below I would like to add a means of extracting each checkbox "checked" status and adding a "X" in the first and/or second position of variable Str, whenever a checkbox has been checked.  Thus far I have not been successful; all conditions show the checkboxes as unchecked.  The boxes are set in another routine using this same method and autopostback = true.  Does anyone know how I can do this?  Extracting text from the remaining columns in Gridview works fine.

            Dim X As Integer = 0
            Dim index As Integer = 0
            Dim Str As String = String.Empty
            Dim Head As String = String.Empty
            Dim builder As New StringBuilder()
            Dim strFileName As String = "GridViewExcel_" & ".slk"
            GridView1.DataBind()

            For X = 0 To 5 Step 1
                Head = Head & GridView1.Columns(X).HeaderText & "|"
            Next
            Head = Head & Environment.NewLine
            builder.Append(Head)

            For Each row As GridViewRow In GridView1.Rows
                Dim PDFB As CheckBox = DirectCast(row.Cells(0).FindControl("PDF"), CheckBox)
                Dim SLDB As CheckBox = DirectCast(row.Cells(1).FindControl("SLDPRT"), CheckBox)

                If PDFB.Checked = True Then
                    PCB = "X" & Convert.ToString("|")
                Else
                    PCB = Convert.ToString("|")
                End If

                If SLDB.Checked = True Then
                    SLD = "X" & Convert.ToString("|")
                Else
                    SLD = Convert.ToString("|")
                End If

                Dim PCBF As String = row.Cells(2).Text & Convert.ToString("|")
                Dim DESC As String = row.Cells(3).Text & Convert.ToString("|")
                Dim HGT As String = row.Cells(4).Text & Convert.ToString("|")
                Dim CMNT As String = row.Cells(5).Text & Convert.ToString("|")
                Str = PCB & SLD & PCBF & DESC & HGT & CMNT
                Str = Str.Replace(" ", "")
                builder.Append(Str & Environment.NewLine)
            Next
            Dim index2 As Integer = 1

            Response.Clear()
            Response.ContentType = "text/slk"
            Response.AddHeader("Content-Disposition", Convert.ToString("attachment;filename=" & Request.QueryString("Data") + "Cutouts and Holes" & ".slk"))
            Response.Write(builder.ToString())
            Response.[End]()

Thanks!

Answer 1

User664436781 posted

1) .aspx C# code:

Include checkbox in header template.

<asp:TemplateField>
   <HeaderTemplate>
      <asp:CheckBox ID="checkAll" runat="server" onclick="checkAll(this);" />
   </HeaderTemplate>
   <HeaderStyle Width="25px" />
   <ItemTemplate>
      <asp:CheckBox ID="CheckBox1" runat="server" OnCheckedChanged="CheckBox1_CheckedChanged" />
   </ItemTemplate>
</asp:TemplateField>

2) .aspx.cs code beind:

Include below methods to populate and repopulate check boxes.

    private void RePopulateCheckBoxes()
    {
        if (ViewState["SELECTED_INDEX"] != null)
        {
            foreach (GridViewRow row in GridView2.Rows)
            {
                var chkBox = row.FindControl("CheckBox1") as CheckBox;

                IDataItemContainer container = (IDataItemContainer)chkBox.NamingContainer;

                if (SelectedIndex != null)
                {
                    if (SelectedIndex.Exists(i => i == container.DataItemIndex))
                    {
                        chkBox.Checked = true;
                    }
                }
            }
        }
    }
    private List<Int32> SelectedIndex
    {
        get
        {
            if (ViewState["SELECTED_INDEX"] == null)
            {
                ViewState["SELECTED_INDEX"] = new List<Int32>();
            }

            return (List<Int32>)ViewState["SELECTED_INDEX"];
        }
    }

    private void RemoveRowIndex(int index)
    {
        SelectedIndex.Remove(index);
    }

    private void PersistRowIndex(int index)
    {
        if (!SelectedIndex.Exists(i => i == index))
        {
            SelectedIndex.Add(index);
        }
    }
    protected void CheckBox1_CheckedChanged(object sender, EventArgs e)
    {
        CheckBox CheckBox1 = (CheckBox)sender;
        int index = ((IDataItemContainer)CheckBox1.NamingContainer).DataItemIndex;
        if (!SelectedIndex.Exists(i => i == index))
            SelectedIndex.Add(index);
        else
            SelectedIndex.Remove(index);
    }

protected void GetSelectedRecords()
{
    // row - GridView Row
    CheckBox chkRow = (row.Cells[0].FindControl("CheckBox1") as CheckBox);
    if (chkRow.Checked)
    {
       //---
    }
}

Above code is in c#, may help in logic.

Answer 2

User-1509636757 posted

all conditions show the checkboxes as unchecked

In which event the code (that you posted) is written? Please check if grid is not being re-binded again (that ultimately making checkbox unchecked making them as initial unchecked state.

Dim PDFB As CheckBox = DirectCast(row.Cells(0).FindControl("PDF"), CheckBox)
                Dim SLDB As CheckBox = DirectCast(row.Cells(1).FindControl("SLDPRT"), CheckBox)

Also try finding control in row directly as:

For Each row As GridViewRow In GRIDVIEW1.Rows
    Dim PDFB As CheckBox = DirectCast(row.FindControl("PDF"), CheckBox)
    Dim SLDB As CheckBox = DirectCast(row.FindControl("SLDPRT"), CheckBox)
Next

Make sure IDs of the Check boxes PDF, SLDPRT are correct.

hope that helps./.

Answer 3

User615288127 posted

Thanks kaushalparik27,

It turns out that I did inadvertently re-bind.  Once that line was removed everything worked fine.