Develop Reference

Unable to persist data in GridView

have a GridView but cannot retrieve any of the data on post-back. I have set a break point at the start of Page_Init and Page_Load, on any post-back that is triggered the GridView.Rows.Count property is always 0. The GridView is defined as shown below:
<asp:GridView ID="TestGrid" runat="server" AllowSorting="False" DataKeyNames="ID,stock,percentage"
OnRowDataBound="GridViewTest_RowDataBound" EnableViewState="True"
OnRowUpdating="GridViewTest_OnRowUpdating" OnRowEditing="GridViewTest_OnRowEditing" OnRowCancelingEdit="GridViewTest_OnRowCancelingEdit"
AutoGenerateColumns="False">
<Columns>
<asp:CommandField ShowEditButton="True" CausesValidation="False"/>
<asp:BoundField DataField="Client" HeaderText="Client" InsertVisible="False" ReadOnly="True" />
<asp:BoundField DataField="Stock" HeaderText="Stock" InsertVisible="False" ReadOnly="True" />
<asp:BoundField DataField="DutyStatus" HeaderText="DutyStatus" InsertVisible="False" ReadOnly="True" />
<asp:TemplateField HeaderText="Percentage" InsertVisible="False">
<ItemTemplate>
<asp:Label ID="enhLbl" runat="server"><%#Eval("Percentage")%></asp:Label>
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="TbPercentage" runat="server" Text="<%#Bind("Percentage")%>" class="edit-field"></asp:TextBox>
</EditItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
I have a check for IsPostBack in Page_Load and only bind the GridView to its DataSource if it's not a post-back.
The only other time it gets re-bound is in the GridViewTest_OnRowEditing, GridViewTest_OnRowUpdating and GridViewTest_OnRowCancelingEdit event handlers.
I am binding the GridView to a DataTable in the following way:
AGridView.DataSource = DataTableSplitParcels;
AGridView.DataBind();
AGridView.EnableViewState = true;
I don't know if it makes any difference, but the DataTable is created in code and the rows added within a loop.
Within Page_Load on a post-back I can see the GridView has its DataKeysArrayList property populated with the current values, however with it having no rows I am unable to retrieve any updated values.

The problem seems in the Page_Load event, which is refreshing your GridView with every call (irrespective of postback), and because of that you are losing what was entered by the user during update.
So put a debugger on your Page_Load and BindData events and see if it is getting called by Page_Load at all, and you need to stop that.. I tried a sample app and it worked at my end.. see below the code that I tried.
ASPX
<asp:GridView ID="TaskGridView" runat="server"
AutoGenerateEditButton="True"
AllowPaging="true"
OnRowEditing="TaskGridView_RowEditing"
OnRowCancelingEdit="TaskGridView_RowCancelingEdit"
OnRowUpdating="TaskGridView_RowUpdating"
OnPageIndexChanging="TaskGridView_PageIndexChanging">
</asp:GridView>
CS
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
// Create a new table.
DataTable taskTable = new DataTable("TaskList");
// Create the columns.
taskTable.Columns.Add("Id", typeof(int));
taskTable.Columns.Add("Description", typeof(string));
taskTable.Columns.Add("IsComplete", typeof(bool));
//Add data to the new table.
for (int i = 0; i < 20; i++)
{
DataRow tableRow = taskTable.NewRow();
tableRow["Id"] = i;
tableRow["Description"] = "Task " + i.ToString();
tableRow["IsComplete"] = false;
taskTable.Rows.Add(tableRow);
}
//Persist the table in the Session object.
Session["TaskTable"] = taskTable;
//Bind data to the GridView control.
BindData();
}
}
protected void TaskGridView_RowUpdating(object sender, GridViewUpdateEventArgs e)
{
//Retrieve the table from the session object.
DataTable dt = (DataTable)Session["TaskTable"];
//Update the values.
GridViewRow row = TaskGridView.Rows[e.RowIndex];
dt.Rows[row.DataItemIndex]["Id"] = ((TextBox)(row.Cells[1].Controls[0])).Text;
dt.Rows[row.DataItemIndex]["Description"] = ((TextBox)(row.Cells[2].Controls[0])).Text;
dt.Rows[row.DataItemIndex]["IsComplete"] = ((CheckBox)(row.Cells[3].Controls[0])).Checked;
//Reset the edit index.
TaskGridView.EditIndex = -1;
//Bind data to the GridView control.
BindData();
}
private void BindData()
{
TaskGridView.DataSource = Session["TaskTable"];
TaskGridView.DataBind();
}
Source available here

Pass Gridview one Row TextBox value To Another Row Textbox Value

I have Gridview with 10 Rows each row have 2 columns which is Textbox and Checkbox.
what i have to do is have to enter textbox Value as 1000 and i Clicked the Checkbox at first Row then value must go to Textbox of Second row and i clicked checkbox of Second Row then value must be go to third row of Textbox and so on.
i tried this,
protected void txtintroId_TextChanged(object sender, EventArgs e)
{
TextBox txt = (TextBox)sender;
GridViewRow grid = ((GridViewRow)txt.Parent.Parent.Parent);
TextBox txtIntro = (TextBox)txt.FindControl("txtintroId");
}
here i get the 1st row Value but How do i pass this to second Row.
Assist me

Here is full working code(as per your requirement )
Create a gridview like this
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="false">
<Columns>
<asp:TemplateField>
<ItemTemplate>
<asp:TextBox ID="TextBox1" runat="server" Text='<%#Eval("txtcolumn") %>'></asp:TextBox>
</ItemTemplate>
</asp:TemplateField>
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="CheckBox1" runat="server" AutoPostBack="True" OnCheckedChanged="CheckBox2_CheckedChanged" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
Add a function in code behind C#
protected void CheckBox1_CheckedChanged(object sender, EventArgs e)
{
int rowNo=0;
foreach (GridViewRow GV1 in GridView1.Rows)
{
rowNo++;//
if (rowNo < GridView1.Rows.Count) //Checking that is this last row or not
{
//if no
CheckBox chkbx= (CheckBox)GV1.FindControl("CheckBox1");
TextBox curenttxtbx = (TextBox)GV1.FindControl("TextBox1");
if (chkbx.Checked == true )
`{
int nextIndex = GV1.RowIndex + 1;//Next row
TextBox txtbx = (TextBox)GridView1.Rows[nextIndex].FindControl("TextBox1");
txtbx.Text = curenttxtbx.Text;
}
}
//if yes
else
{
//For last row
//There is no next row
}
}
}
And i used this data table as data source
DataTable table = new DataTable();
table.Columns.Add("txtcolumn", typeof(string));
table.Rows.Add("1");
table.Rows.Add("32");
table.Rows.Add("32");
table.Rows.Add("32");
table.Rows.Add("3");
table.Rows.Add("32");
table.Rows.Add("32");
I tested this code it is working as per your requirement. (And SORRY for this bad formatting. i will do it later or please some body correct the formating :))

Repeater and Collapsible Panel Extender

I am trying to bind a grid view into a repeater for collapsible panel extender body. Here is the code:
<!-- Collapsible panel extender body -->
<asp:Panel ID="pBody1" runat="server" CssClass="cpBody">
<asp:Label ID="lblBodyText1" runat="server" />
<asp:Repeater ID="Repeater2" runat="server" OnItemDataBound="Repeater2_ItemDataBound">
<ItemTemplate>
<asp:GridView ID="gvProduct" runat="server" AutoGenerateColumns="False">
<Columns>
<asp:BoundField DataField="id" HeaderText="ID" />
<asp:BoundField DataField="name" HeaderText="Name" />
<asp:BoundField DataField="categoryName" HeaderText="Category" />
<asp:BoundField DataField="inventoryQuantity" HeaderText="Quantity" />
</Columns>
</asp:GridView>
</ItemTemplate>
</asp:Repeater>
</asp:Panel>
And from the code behind, I am trying to loop thru the list to get category name. Then, I get all the products based on category name and display them in gridview.
protected void Repeater2_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
// This event is raised for the header, the footer, separators, and items.
//Execute the following logic for Items and Alternating Items.
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
for (int count = 0; count < categoryList.Count; count++)
{
string category = categoryList[count].categoryName;
List<ProductPacking> prodList = new List<ProductPacking>();
prodList = packBLL.getAllProductByCategory(category);
gvProduct.DataSource = prodList;
gvProduct.DataBind();
}
}
}
However, it told me that gvProduct does not exist in current context. I wonder how can I get the components inside a repeater? Or am I doing in the wrong way?
Updated Portion.
This is how I bind the header for category name. And I am using another repeater:
<asp:Label ID="lblCategory" Text='<%# DataBinder.Eval(Container.DataItem, "categoryName") %>' runat="server" />
And from the code behind, at the page load, I get all the category:
if (!IsPostBack)
{
//Get all category and bind to repeater to loop
categoryList = packBLL.getAllCategory();
Repeater1.DataSource = categoryList;
Repeater1.DataBind();
}
And for repeater2 which shows the product in each category, I edited it to become like this:
protected void Repeater2_ItemDataBound(object sender, RepeaterItemEventArgs e)
{
// This event is raised for the header, the footer, separators, and items.
string category = e.Item.FindControl("categoryName").ToString();
//Execute the following logic for Items and Alternating Items.
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
GridView gv = (GridView)e.Item.FindControl("gvProduct");
if (gv != null)
{
List<ProductPacking> prodList = new List<ProductPacking>();
prodList = packBLL.getAllProductByCategory(category);
DataRowView drv = (DataRowView)e.Item.DataItem;
gv.DataSource = prodList;
gv.DataBind();
}
}
}
However, when I expand the extender, nothing shows up.

If I remember right, you need to use FindControl to access controls that are part of templates, like
GridView oGV = e.Item.FindControl ( "gvProducts" ) as GridView;
You cannot refer to the GridView as gvProducts because there's no single GridView control with that name - a different instance (with a different name) is created for each data item from the template. You need the instance for the current row.
Here's an MSDN example that shows how to access a control during data binding (the example uses a Label).

Dynamic control Viewstate

I am now stuck. After spending ages trying to maintain dynamically added linkbutton or label to a gridview it seems I am overwriting a checkbox state on post back.
As stated I am dynamically adding either a linkbutton or a label to a place holder in a gridview with the following:
protected void LedgerGrid_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType == DataControlRowType.DataRow)
{
int index = e.Row.RowIndex;
if (items[index].noteID > 0)
{
PlaceHolder label = (PlaceHolder)e.Row.FindControl("HasPrevious");
LinkButton link = new LinkButton();
link.CommandName = "LinkCommand";
link.Command += new CommandEventHandler(link_Command);
link.Text = "Yes";
link.ID = index.ToString();
label.Controls.Add(link);
}
else
{
PlaceHolder label = (PlaceHolder)e.Row.FindControl("HasPrevious");
Label noNote = new Label();
noNote.Text = "No";
label.Controls.Add(noNote);
}
Here is the gridview:
<asp:GridView runat="server" ID="LedgerGrid" AutoGenerateColumns="false"
onselectedindexchanged="LedgerGrid_SelectedIndexChanged"
onrowdatabound="LedgerGrid_RowDataBound" onrowcommand="LedgerGrid_RowCommand"
>
<Columns>
<asp:TemplateField HeaderText="Notes">
<ItemTemplate>
<asp:PlaceHolder ID="HasPrevious" runat="server"></asp:PlaceHolder>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField HeaderText="Invoice Date" DataField="invoicedate" DataFormatString="{0:d}" />
<asp:BoundField HeaderText="Invoice" DataField="invoice" />
<asp:BoundField HeaderText="Fee Debt" DataField="Fee_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="Cost Debt" DataField="Cost_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="VAT Debt" DataField="VAT_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="Total Debt" DataField="Total_Debt" DataFormatString="{0:C}" />
<asp:BoundField HeaderText="Client Code" DataField="ClientCode" />
<asp:ButtonField HeaderText="Matter Number" DataTextField="matternumber" CommandName="ViewMatter" />
<asp:BoundField HeaderText="Decription" DataField="matterdescription" />
<asp:TemplateField>
<ItemTemplate>
<asp:CheckBox ID="AddInvoiceCheck" runat="server" Enabled="true" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>
To make sure that my link button command works I am rebuilding the gridview as I would in the Page_load. Here is the page load:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
string clientCode = Server.HtmlEncode(Request.QueryString["clientcode"]);
items = DataAccess.DataAccess.GetLedgerDetails(clientCode);
ViewState["LedgerItems"] = items;
ViewState["clientcode"] = clientCode;
LedgerGrid.DataSource = items;
LedgerGrid.DataBind();
LedgerClientObject clientDetails = DataAccess.DataAccess.GetClientDetails(clientCode);
ClientCodeLabel.Text = string.Format("Group Code: {0}", clientDetails.GroupCode);
ClientNameLabel.Text = string.Format("Client Name: {0}", clientDetails.ClientName);
ClientCodeFilter.DataSource = clientDetails.ClientCodes;
ClientCodeFilter.DataBind();
}
}
To maintain the dynamically added controls on post back I am calling the following:
protected void Page_PreLoad(object sender, EventArgs e)
{
if (IsPostBack)
{
items = (List<LedgerItem>)ViewState["LedgerItems"];
LedgerGrid.DataSource = items;
LedgerGrid.DataBind();
}
}
Of course it now seems that by using this method I am overwriting the state of the check-box gridview column. Am I approaching this all wrong? I would like to be able to use the viewstate to maintain the set up of my dynamically added controls to the gridview. Is there a way I can access the state of the checkbox control form gridview before/after I reload the gridview in PreLoad event?
I am checking the state of my checkbox column with a button click as follows:
protected void Unnamed1_Click(object sender, EventArgs e)
{
NoteModel note = new NoteModel();
for (int i = 0; i < LedgerGrid.Rows.Count; i++)
{
int invoice = Convert.ToInt32(LedgerGrid.Rows[i].Cells[2].Text);
CheckBox check = (CheckBox)LedgerGrid.Rows[i].FindControl("AddInvoiceCheck");
if (check.Checked)
{
note.invoices.Add(invoice);
}
}
if (note.invoices == null)
{
string clientcode = (string)ViewState["clientcode"];
ViewState["InvoiceError"] = 1;
Response.Redirect(string.Format("Ledger.aspx?clientcode={0}", clientcode));
}
else
{
string clientcode = (string)ViewState["clientcode"];
Session["NoteObject"] = note;
Response.Redirect(string.Format("AddNote.aspx?cc={0}", clientcode));
}
}
Whenever I iterate over the checkbox controls in the gridview they are all unchecked e.g overwritten by my PreLoad code!!!

In the end I decided not to use dynamically created controls. Instead I added a buttonfield to the grid view. In my rowdatabound event I then set the visibility of the button to false if it does meet my criteria. This way view state is maintained as i do not need to create control on post back.
Seems with webforms that avoiding dynamic controls where possible is the best bet. I would still like to know which event to tap into to override viewstate re-instating controls?

Adding Querystring Parameter to GridView ItemTemplate

I have a gridview with a hyperlink in first column. Upon clicking the hyperlink, the user is redirected to Vendor.aspx. Now, I need to pass the consumer id (of the clicked row) as a query string to the Vendor.aspx.
What is the best method to achieve it? Is there a way in which we can handle it using markup code only?
<asp:GridView ID="grdConsumers" runat="server" AutoGenerateColumns="False"
EnableViewState="True" >
<Columns>
<asp:TemplateField HeaderText="ConsumerID" SortExpression="ConsumerID" >
<ItemTemplate>
<asp:HyperLink ID="lnkConsumerID" href="Vendor.aspx" runat="server"><%# Eval("ConsumerID")%></asp:HyperLink>
</ItemTemplate>
</asp:TemplateField>
<asp:BoundField HeaderText="Status" DataField="Status" SortExpression="Status"></asp:BoundField>
</Columns>
</asp:GridView>
READINGS:
Set Gridview DataNavigateUrlFormatString Dynamically inside User Control(ASCX)
How do I add "&Source" to DataNavigateUrlFormatString?
Select row in GridView with JavaScript
How to bind the URL of a GridView HyperLinkField when the bound value contains a colon?
asp.net gridview DataNavigateUrlFormatString from DataSource

Try using the DataNavigateUrlFormatString
<ItemTemplate>
<asp:HyperLinkField DataNavigateUrlFields="ConsumerID" DataTextField="ConsumerID" DataNavigateUrlFormatString="Vendor.aspx?id={0}" />
</ItemTemplate>
... it will spare you Eval() and the problem with single/double quotes when putting it inside your href.
You can substitute the DataTextField if you like - I just put the ConsumerID there to be consistent with your example.

Rewrite your hyperlink in gridview in .aspx file like this:
<asp:HyperLink ID="lnkConsumerID" runat="server" Text='<%# Eval("ConsumerID")%>' />
Then in code-behind create a RowDataBound event handler:
protected void grdConsumers_RowDataBound(object sender, GridViewRowEventArgs e)
{
if (e.Row.RowType != DataControlRowType.DataRow) return;
var hlnkhlnk = (HyperLink)e.Row.FindControl("lnkConsumerID");
if (hlnkhlnk != null)
{
hlnkhlnk.NavigateUrl = "Vendor.aspx" + "?Consumer ID=" + hlnkhlnk.Text;
}
}
Hope it helps.

You can do same using at Grid view Item Data Bound Event
protected void grdConsumers_ItemDataBound(object sender,DataGridItemEventArgs e)
{
if(e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
// Get your consumerId here
((HyperLink)e.Item.FindControl("Edit")).NavigateUrl = "Vendor.aspx?id=" + consumerId
}
}