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Asp.net datalist select all checkboxes for each category

I have a page where users can select different document files in a datalist control. Documents are classified into categories using a preprocessing event handler. Documents are selected based on Checkbox controls (not Checkboxlist). So far, so good. Next, I want to check the "Select All" box next to each category name, which should only select the checkboxes under that category. Here is the datalist control:

<asp:DataList ID="DataList1" runat="server" RepeatDirection="Vertical" OnPreRender="DataList1_PreRender" DataKeyField="docid" EnableViewState="false">
<ItemTemplate>
    <table cellpadding="0" cellspacing="0" id="tbl_data">
        <tr>
            <td>
                <asp:Label ID="lblHeader" runat="server" Font-Bold="True" Font-Underline="True"></asp:Label>
             <asp:Label runat="server" id="lbl_cb_all" visible="false">Select All <input runat="server" id="cb_selectall" type="checkbox" value='<%# Eval("catid") %>' /> </asp:Label>
            </td>
        </tr>

        <tr runat="server" id="tr_data">
            <td>
                <asp:Label ID="lbl_categoryname" runat="server" Text='<%# Eval("categoryname") %>' Visible="false" /> <!-- Hide this; only used in Code Behind -->
                 <input runat="server" id="cb_docid" type="checkbox" value='<%# Eval("docid") %>' />
                  <asp:Hyperlink ID="hpl_docfileencr" Text='<%# Eval("docfileencr") %>' NavigateUrl='<%# "~/PDFEncr/" + DataBinder.Eval(Container.DataItem, "docfileencr") %>' Target="_blank"  runat="server" />
                <br />
            </td>
        </tr>
    </table>
</ItemTemplate>

and here is the OnPreRender code:

protected void DataList1_PreRender(object sender, EventArgs e)
{
    string strTempLabelCategory = "";
    foreach (DataListItem item in DataList1.Items)
    {



        Label lbl_categoryname = item.FindControl("lbl_categoryname") as Label;


        if (strTempLabelCategory.ToUpper() != lbl_categoryname.Text.ToString().ToUpper())
        {
            strTempLabelCategory = lbl_categoryname.Text.ToString().ToUpper();
            Label lblHeader = item.FindControl("lblHeader") as Label;
            lblHeader.Text = strTempLabelCategory.ToUpper();

            Label lbltempdiv = item.FindControl("lbl_cb_all") as Label;
            lbltempdiv.Visible = true;
        }
    }
}

I was looking for something that might work in my code but no luck. And I am too nested in this code to try the Checkboxlist handler (not sure if it helps anyway). Any ideas? I thought I could use: http://www.dotnetcurry.com/ShowArticle.aspx?ID=77 code but don't know how I can do it? If I can somehow bind a checkmark to a tag and then search for all tags, then maybe the link code will help. Thank!

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2 answers


  • Use HiddenFields to store CatID

    andDocID

  • Use ASP.NET Controls instead of HTML Inputs for
  • Edit the "Check-All Checkbox" CheckedChanged

    :


protected void CheckAllChanged(Object sender, EventArgs e)
{
    CheckBox checkAll = (CheckBox)sender;
    DataListItem item = (DataListItem)checkAll.NamingContainer;
    HiddenField HiddenCatID = (HiddenField)item.FindControl("HiddenCatID");
    var catCheckBoxes = DataList1.Items.Cast<DataListItem>()
        .Where(li => ((HiddenField)li.FindControl("HiddenCatID")).Value == HiddenCatID.Value)
        .Select(li => li.FindControl("cb_docid"));
    foreach (CheckBox docCheckBox in catCheckBoxes)
    {
        docCheckBox.Checked = checkAll.Checked;
    }
}

in aspx:

<asp:CheckBox runat="server" OnCheckedChanged="CheckAllChanged" AutoPostBack="true"  id="cb_selectall" />
<asp:HiddenField ID="HiddenCatID" runat="server" Value='<%# Eval("CatID") %>' />
<asp:HiddenField ID="HiddenDocID" runat="server" Value='<%# Eval("DocID") %>' />

You also need EnableViewState=true

to store the checkbox state in the DataList and enable check / uncheck.



Edit

Since you have trouble getting it running, here is a complete working example page.

Here are the required aspx controls (note fe <tr runat="server" id="tr_category">)

:

<ItemTemplate>
    <table cellpadding="0" cellspacing="0" id="tbl_data">
        <tr runat="server" id="tr_category">
            <td>
                <asp:Label ID="lblHeader" runat="server" Font-Bold="True" Text='<%# Eval("categoryname") %>' Font-Underline="True"></asp:Label>
                <asp:Label runat="server" ID="lbl_cb_all">Select All
                <asp:CheckBox runat="server"  OnCheckedChanged="CheckAllChanged" AutoPostBack="true"  id="cb_selectall" />
                </asp:Label>
            </td>
        </tr>
        <tr runat="server" id="tr_data">
            <td>
                <asp:HiddenField ID="HiddenCatID" runat="server" Value='<%# Eval("CatID") %>' />
                <asp:CheckBox runat="server" id="cb_docid" />
                <asp:HyperLink ID="hpl_docfileencr" Text='<%# Eval("docfileencr") %>' NavigateUrl='<%# "~/PDFEncr/" + DataBinder.Eval(Container.DataItem, "docfileencr") %>'
                    Target="_blank" runat="server" />
                <br />
            </td>
        </tr>
    </table>
</ItemTemplate>

  • Make sure the DataList is only bound to the database if(!IsPostback)

    , otherwise the checkbox selection will not be saved:

    protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack) BindDataList();
}

  • I use ItemDataBound

    instead PreRender

    , which is important to properly reload the ViewState. I've also simplified everything:

    protected void DataList1_ItemDataBound(Object sender, DataListItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType==ListItemType.AlternatingItem)
    {
        var row  = (DataRowView)e.Item.DataItem;
        var view = row.DataView;
        var lastRow = e.Item.ItemIndex == 0 ? null : view[e.Item.ItemIndex-1];
        var tr_category = (System.Web.UI.HtmlControls.HtmlTableRow)e.Item.FindControl("tr_category");
        var sameCategory = lastRow != null && (int)row["catid"] == (int)lastRow["catid"];
        tr_category.Visible = !sameCategory;
    }
}

  • CheckAllChanged

    remains unchanged.

This works as expected, even if you select one checkbox for the document and check the category checkbox that triggers the postback.

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I think I got this to work with a slight modification to Tim's code. A couple of points: I had to disable the ViewState for the datalist because the check-all trigger would otherwise not check the checkboxes. I do not understand why. In addition, there is no ispostback check on the page_load event, and the datalist binding is bound to every load. I'm not that "optimal" or not. I also made two sets of Asp: RadioButtons: CheckAll and CheckNone instead of checkboxes. Anyway, here's the relevant code:

<asp:DataList ID="DataList1" runat="server" RepeatDirection="Vertical" DataKeyField="docid"
                EnableViewState="false" OnItemDataBound="DataList1_ItemDataBound">
                <ItemTemplate>
                    <table cellpadding="0" cellspacing="0" id="tbl_data">
                        <tr runat="server" id="tr_category">
                            <td>
                                <asp:Label ID="lblHeader" runat="server" Font-Bold="True" Text='<%# Eval("categoryname") %>'
                                    Font-Underline="True"></asp:Label>
                                <asp:Label runat="server" ID="lbl_cb_all">Select: All
                                    <asp:RadioButton runat="server" OnCheckedChanged="CheckAllChanged" AutoPostBack="true"
                                        ID="rb_selectall" GroupName="selectallnone" />
                                    | None
                                    <asp:RadioButton runat="server" OnCheckedChanged="CheckAllChangedNone" AutoPostBack="true"
                                        ID="rb_selectnone" GroupName="selectallnone" />
                                    <asp:HiddenField ID="HiddenCatID" runat="server" Value='<%# Eval("CatID") %>' />
                                    <asp:HiddenField ID="HiddenDocID" runat="server" Value='<%# Eval("docid") %>' />
                                </asp:Label>
                            </td>
                        </tr>
                        <tr runat="server" id="tr_data">
                            <td>
                                <asp:CheckBox runat="server" ID="cb_docid" Value='<%# Eval("docid") %>' />
                                <asp:HyperLink ID="hpl_docfileencr" Text='<%# Eval("docfileencr") %>' NavigateUrl='<%# "~/PDFEncr/" + DataBinder.Eval(Container.DataItem, "docfileencr") %>'
                                    Target="_blank" runat="server" />
                                <br />
                            </td>
                        </tr>
                    </table>
                </ItemTemplate>
            </asp:DataList>

 protected void DataList1_ItemDataBound(Object sender, DataListItemEventArgs e)
{
    if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
    {
        var row = (DataRowView)e.Item.DataItem;
        var view = row.DataView;
        var lastRow = e.Item.ItemIndex == 0 ? null : view[e.Item.ItemIndex - 1];
        var tr_category = (System.Web.UI.HtmlControls.HtmlTableRow)e.Item.FindControl("tr_category");
        var sameCategory = lastRow != null && (int)row["catid"] == (int)lastRow["catid"];
        tr_category.Visible = !sameCategory;
    }
}

protected void CheckAllChanged(Object sender, EventArgs e)
{
    RadioButton checkAll = (RadioButton)sender;
    DataListItem item = (DataListItem)checkAll.NamingContainer;
    HiddenField HiddenCatID = (HiddenField)item.FindControl("HiddenCatID");

    var catCheckBoxes = DataList1.Items.Cast<DataListItem>()
        .Where(li => ((HiddenField)li.FindControl("HiddenCatID")).Value == HiddenCatID.Value)
        .Select(li => li.FindControl("cb_docid"))
        .ToList();
    foreach (CheckBox docCheckBox in catCheckBoxes)
    {
       // docCheckBox.Checked = checkAll.Checked;
        docCheckBox.Checked = true;
    }
 }

protected void CheckAllChangedNone(Object sender, EventArgs e)
{
    RadioButton checkAll = (RadioButton)sender;
    DataListItem item = (DataListItem)checkAll.NamingContainer;
    HiddenField HiddenCatID = (HiddenField)item.FindControl("HiddenCatID");

    var catCheckBoxes = DataList1.Items.Cast<DataListItem>()
        .Where(li => ((HiddenField)li.FindControl("HiddenCatID")).Value == HiddenCatID.Value)
        .Select(li => li.FindControl("cb_docid"))
        .ToList();

    foreach (CheckBox docCheckBox in catCheckBoxes)
    {
        docCheckBox.Checked = false;
    }


}


// the partial code from the "Order" button is executed; note the use of HiddenField

 CheckBox cb = li.FindControl("cb_docid") as CheckBox;

        if (cb != null)
        {
            if (cb.Checked)
            {
                HiddenField docid = li.FindControl("HiddenDocID") as HiddenField;
                string dbcmd = @"Insert Into [order_details] (orderid,docid) Values (" + orderid + "," + docid.Value.ToString() + ")";
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