I have a simple RadMultiColumnComboBox in my aspx page with tag
<telerik:RadMultiColumnComboBox ID="RadMultiColumnComboBox1" RenderMode="Lightweight" runat="server" Filter="StartsWith" OnItemDataBound="RadMultiColumnComboBox1_ItemDataBound">
</telerik:RadMultiColumnComboBox>
How can I add ColumnsCollection-->MultiColumnComboBoxColumn fields from code behind.
What I am trying to achieve is creating a user control for MultiColumnComboBox so that it can be reused in various screens as per my need. Thus each page has different data and I need to bind the data from code behind instead of doing it from the design page like:
<telerik:RadMultiColumnComboBox runat="server" ID="RadMultiColumnComboBox1"
Width="220px" Height="400"
DataTextField="text" DataValueField="value">
<ColumnsCollection>
<telerik:MultiColumnComboBoxColumn Field="text" Title="Text">
</telerik:MultiColumnComboBoxColumn>
<telerik:MultiColumnComboBoxColumn Field="value" Title="Value">
</telerik:MultiColumnComboBoxColumn>
</ColumnsCollection>
</telerik:RadMultiColumnComboBox>
Please help.
Got the solution.
RadMultiColumnComboBox1.DataValueField = "ID";
RadMultiColumnComboBox1.DataTextField = "Name";
foreach (DataColumn item in dt.Columns)
{
RadMultiColumnComboBox1.ColumnsCollection.Add(new MultiColumnComboBoxColumn()
{
Field = item.ColumnName,
Title = item.ColumnName
});
}
RadMultiColumnComboBox1.DataSource = dt;
RadMultiColumnComboBox1.DataBind();
You have to fetch the data from DB into the data table
I have this dropdownlist in an ASP.NET page:
<asp:DropDownList ID="lstField1" runat="server">
<!--#include virtual="../path/to/myListOfValues.asp"-->
</asp:DropDownList>
Contents of "myListOfValues.asp" file:
<asp:ListItem value="%">Select value</asp:ListItem>
<asp:ListItem value="1">Value #1</asp:ListItem>
<asp:ListItem value="2">Value #2</asp:ListItem>
<asp:ListItem value="3">Value #3</asp:ListItem>
<asp:ListItem value="4">Value #4</asp:ListItem>
At some point of the page's execution, I change the items of this dropdownlist. But, eventually, i need to reload the items from the .asp file.
is there any way to "restore" the items from the .asp file, i.e. changing the dropdownlist's "innerHTML" or something like that?
Thanks in advance.
EDIT
I found a way:
1) Having a delimited string with the values i need to exclude from the items.
2) Splitting the delimited string
3) Looping the resultant array, and
4) Searching for the value in the dropdownlist. If the value is found, I disable it.
Something just like this:
'split the excluded items list
Dim arrExcludedItems() As String = myExcludedList.Split("|")
'enable all the dropdownlist's items.
For i As Integer = 0 To Me.lstField1.Items.Count - 1
Me.lstField1.Items(i).Enabled = True
Next
'search for the excluded item in the dropdownlist
'if it's found, disable the respective item.
For i As Integer = 0 To UBound(arrExcludedItems)
Me.lstField1.Items.FindByValue(arrExcludedItems(i)).Enabled = False
Next
Hope it helps for anyone.
Best regards,
I did some testing. I could not figure out how to rebind data from an asp file. But that does not mean you cannot achieve what you want. This snippet stores the original ListItems in ViewState so that you can bind the orignal ones later on.
<asp:DropDownList ID="lstField1" runat="server">
<!--#include virtual="/myListOfValues.asp"-->
</asp:DropDownList>
<asp:Button ID="Button1" runat="server" Text="Bind new data" OnClick="Button1_Click" />
<asp:Button ID="Button2" runat="server" Text="Bind original data" OnClick="Button2_Click" />
Code behind
protected void Button1_Click(object sender, EventArgs e)
{
//create a new list to hold the original listitems
var list = new List<KeyValuePair<string, string>>();
//loop all the listitems and add them to the list
foreach (ListItem item in lstField1.Items)
{
list.Add(new KeyValuePair<string, string>(item.Value, item.Text));
Response.Write(item.Text);
}
//add the list to viewstate for later usage
ViewState["tempList"] = list;
//clear the list of its current items
lstField1.Items.Clear();
//add the new items to the dropdownlist
lstField1.Items.Add(new ListItem() { Text = "Item 1", Value = "1" });
lstField1.Items.Add(new ListItem() { Text = "Item 2", Value = "2" });
}
protected void Button2_Click(object sender, EventArgs e)
{
//load the list from viewstate and cast it back to a keyvalue list
var list = ViewState["tempList"] as List<KeyValuePair<string, string>>;
//clear the list of its current items
lstField1.Items.Clear();
//add the original items to the dropdownlist
foreach (var item in list)
{
lstField1.Items.Add(new ListItem() { Text = item.Value, Value = item.Key });
}
}
I use asp checkboxlist to have that result
But using html tag as item of the checkboxlist , asp is interpreting it as html. It works for simple text. Here is my result.
and here is the declaration and binding method
<asp:CheckBoxList ID="chklstreponse" runat="server">
</asp:CheckBoxList>
DataTable dtreponse = gq.GetRandom_Responses(Convert.ToInt32(idquest.Value));
chkList.DataSource = dtreponse;
chkList.DataTextField = "libelle";
chkList.DataValueField = "id";
chkList.DataBind();
I think you need to HtmlEncode the values in the RadioButtonList.
System.Net.WebUtility.HtmlEncode("<html>")
But you are binding a datatable directly, you either must do it in the source of the DataTable or loop all rows and encode them.
foreach (DataRow row in dtreponse.Rows)
{
row["libelle"] = System.Net.WebUtility.HtmlEncode(row["libelle"].ToString());
}
chkList.DataSource = dtreponse;
chkList.DataTextField = "libelle";
chkList.DataValueField = "id";
chkList.DataBind();
Try this.HtmlEncode makes sure that text is displayed correctly in the browser and not interpreted by the browser as HTML.
<asp:CheckBoxList ID="chklstreponse" runat="server"> </asp:CheckBoxList>
DataTable dtreponse = gq.GetRandom_Responses(Convert.ToInt32(idquest.Value));
chkList.DataSource = dtreponse;
chkList.DataTextField = Server.HtmlEncode("libelle");
chkList.DataValueField = "id";
chkList.DataBind();
I am working on an ASP.NET VB.NET web form - a reservation web application, in which only one aspx page and rest are user-control page.
At run-time of aspx page, user controls load as per step and name define in db, like in below link.
ASP.NET Custom user control to add dynamically
In the first step, the first user-control is bind in page-init which is used to shows reservation availability detail in .NET datalist control like (see images).
All the details are bind to generate run-time control via data-list's item_databound event.
ImageOfRoom (asp.net Image Control) - on click popup will open with scroll functionality
Name (direct databound)
Amenities (icon(s)) - dynamically add from db.
No. of room as per room type (asp.net dropdown control) - dynamically add from db and on selected index changed, need another dropdown bind in same row and on change of adult dropdown price will vary.
Total price (direct databound)
Book now (button)
Now issue is whenever any event of datalist(click on romm-image or dropdown selected index changed) fired, the dynamic control remove like ammenities, dynamic dropdown of other row etc.
What I tried as :- ispostback, relevant event of page-life cycle, ajax-jquery, viewstate.
I checked this also, But no luck. :
Dynamically added controls in Asp.Net
I analyze that, the user-control is always rebound and then event fired, but no datalist rebind and thus no - databound event fire and finally dynamic control is removed. If you wish, I will share the code too (but its huge code).
So question is how to retain the dynamic controls and its value when dropdown selected index changed or image click event fired in datalist in usercontrol?
I am not used update-panel, does that work? If yes, then please give sample data.
Good to answer with sample data. Even please suggest that if possible via any other control like grid-view or else, then I ready to change it.
Updated
This is my code
Load User Control code
In aspx page, usercontrol define to load another user control as per current step. This “uc” user control tag in aspx page.
<div id="divPlaceholder" runat="server">
<uc:DynamicControlHost ID="ucDynamicControlHost" runat="server" />
</div>
In page_load as well as page_prerender( ispostback ) , the below code execute to load runtime user-control.
public Control SetUserControlPath(string path)
{
Control c = null;
if (this.dynamicAllContent.Controls.Count > 0)
{
//Check that the new control is not the same as the current control
if (!this.UserControlPath.Equals(path))
{
//Remove the old item because we can not simply replace them!
this.dynamicPHAllContent.Controls.Clear();
c = Page.LoadControl(path + ".ascx");
c.ID = path;
//Add New Item
this.dynamicAllContent.Controls.Add(c);
lock (_userControlLockObject)
{
//Store the new path
_strUserControl = path;
}
}
}
else
{
c = Page.LoadControl(path + ".ascx");
c.ID = path;
this.dynamicAllContent.Controls.Add(c);
_strUserControl = path;
}
return c;
}
Structure of datalist in usercontrol
<asp:UpdatePanel ID="EmployeesUpdatePanel" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:DataList ID="dlLodgingAvailableDetails" ShowHeader="true" OnSelectedIndexChanged="dlLodgingAvailableDetails_SelectedIndexChanged" runat="server" CellPadding="2" CellSpacing="2" BorderWidth="1px" BorderColor="Black"
OnItemDataBound="dlLodgingAvailableDetails_ItemDataBound" BorderStyle="Solid" GridLines="Horizontal" HorizontalAlign="Justify">
<HeaderStyle CssClass="submit_butt"></HeaderStyle>
<HeaderTemplate>
Lodging Item Type Details
<asp:Button ID="btnBookRoom" runat="server" Text="Book Rooms" CssClass="submit_butt" OnClick="btnBookRoom_Click" />
</HeaderTemplate>
<ItemTemplate>
<table cellpadding="2" cellspacing="0" border="1" style="width: 100%";>
<tr>
<td style="width:170px">
<asp:ImageButton ID="imgLodging" OnClick="imgLodging_Click" commandargument='<%# Eval("ItemTypeId") %>'
runat="server" ImageUrl='<%# Eval("Photo") %>' Width="150px" Height="120px" />
</td>
<td style="width:180px">
<b>Name</b><br />
<span><%# Eval("ItemTypeName") %></span><br />
<b>Occupancy</b> <span><%# Eval("Occupancy") %></span>
<br />
<asp:panel ID="placeholderAmmenities" runat="server" Visible="True" ></asp:panel>
</td>
<td style="width:100px">
<b>Room</b><br />
<asp:hiddenfield runat="server" ID="hdnItemTypeId" Value='<%# Eval("LodgingItemTypeId") %>' />
<asp:DropDownList ID="ddlAvailable" runat="server"
AppendDataBoundItems="True" SelectedValue='<%# Bind("LodgingReservationsAvailable") %>' >
<asp:ListItem Value="0" Text="0"/>
<asp:ListItem Value="1" Text="1"/>
<asp:ListItem Value="2" Text="2"/>
</asp:DropDownList>
</td>
<td>
</td>
<td style="width:100px">
<div id="dvadult" runat="server"></div>
<asp:placeholder runat="server" ID="PlaceHolderAdult" ViewStateMode="Enabled" EnableTheming="False" Visible="True" ></asp:placeholder>
</td>
<td style="width:50px">
<asp:Label runat="server" ID="lblnumbernight" ></asp:Label>
</td>
<td style="width:50px">
<asp:placeholder ID="placeholderPrice" runat="server" Visible="True"></asp:placeholder>
</td>
<td style="width:50px">
<b>Total</b><br />
<asp:Label runat="server" ID="lblTotalAmount" ></asp:Label>
</td>
<td style="width:100px">
<asp:Button ID="btnBookRoom" runat="server" Text="Book Rooms" CssClass="submit_butt" />
</td>
</tr>
</table>
</ItemTemplate>
<SeparatorStyle BackColor="Lime" Font-Bold="False" Font-Italic="False" Font-Overline="False" Font-Strikeout="False" Font-Underline="False" HorizontalAlign="Center" />
</asp:DataList>
</ContentTemplate>
</asp:UpdatePanel>
Datalist item data bound event code (its inside image binding , price related field add and also creating the dynamic control as per the condition)
protected void dlLodgingAvailableDetails_ItemDataBound(object sender, DataListItemEventArgs e)
{
try
{
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
Image img = e.Item.FindControl("imgLodging") as Image;
if (img != null)
{
string bytesval = ((System.Data.DataRowView)(e.Item.DataItem)).Row.ItemArray[3].ToString();
if (string.IsNullOrWhiteSpace(bytesval)) return;
byte[] bytes = (byte[])((System.Data.DataRowView)(e.Item.DataItem)).Row.ItemArray[3];
string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
img.ImageUrl = "data:image/png;base64," + base64String;
}
DropDownList ddlList = e.Item.FindControl("ddlAvailable") as DropDownList;
Label lbldipositamount = e.Item.FindControl("lblTotalAmount") as Label;
Label lblnumbernight = e.Item.FindControl("lblnumbernight") as Label;
var PlaceHolderAmmenities = e.Item.FindControl("placeholderAmmenities") as Panel;
ddlList.Attributes.Add("onchange", " openLodgingNumber1(this,'" + ddlList.SelectedValue + "');");
int? LodgingItemTypeId = Convert.ToInt32(((System.Data.DataRowView)(e.Item.DataItem)).Row.ItemArray[1]);
DataSet ds = new DataSet();
ds = LodgingData.SelectLodgingItemTypeAmenityDateSet(LodgingItemTypeId);
DataTable dt = new DataTable();
if (ds != null)
{
dt = ds.Tables[0];
if (dt.Rows.Count > 0)
{
for (int j = 0; j < dt.Rows.Count; j++)
{
Image image = new Image();
image.ID = "imgAmmenities" + j + DateTime.Now.ToString();
string bytesval = dt.Rows[j]["AmenityIcon"].ToString(); //((System.Data.DataRowView)(e.Item.DataItem)).Row.ItemArray[4].ToStrin();
//if (string.IsNullOrWhiteSpace(bytesval)) return;
if (bytesval != string.Empty)
{
byte[] bytes = (byte[])dt.Rows[j]["AmenityIcon"];
string base64String = Convert.ToBase64String(bytes, 0, bytes.Length);
image.ImageUrl = "data:image/png;base64," + base64String;
image.Height = 20;
image.Width = 20;
image.EnableViewState = true;
PlaceHolderAmmenities.Controls.Add(image);
PlaceHolderAmmenities.Controls.Add(new LiteralControl(" "));
}
}
}
}
decimal PriceTotal = 0;
var PlaceHolderPrice = e.Item.FindControl("placeholderPrice") as PlaceHolder;
DataSet dsprice = new DataSet();
dsprice = LodgingData.SelectLodgingItemTypePrice(LodgingItemTypeId);
if (dsprice != null)
{
DataTable dtprice = new DataTable();
dtprice = dsprice.Tables[0];
if (dtprice.Rows.Count > 0)
{
DateTime fromdate = Convert.ToDateTime(txtFromDate.Text);
DateTime todate = Convert.ToDateTime(txtToDate.Text);
double daterange = ((todate - fromdate).TotalDays + 1);
lblnumbernight.Text = daterange.ToString();
//for (DateTime date = fromdate; date >= todate; date.AddDays(1))
for (int d = 0; d < Convert.ToInt32(daterange); d++ )
{
DateTime date = fromdate.AddDays(d);
//DataView dv = new DataView(dtprice);
DataTable dtprice1 = new DataTable();
DataRow[] rows = dtprice.Select("#" + date + "# >= PriceStartDate AND" + "#" + date + "# <= PriceEndDate");
if (rows.Length > 0)
{
dtprice1 = rows.CopyToDataTable();
}
if (dtprice1.Rows.Count > 0)
{
for (int j = 0; j < dtprice1.Rows.Count; j++)
{
Label lbl = new Label();
string dayofweek = dtprice1.Rows[j]["DayOfWeekId"].ToString();
if (dayofweek.Trim() == eDayOfWeek.All.ToString().Trim())
{
lbl.ID = "lbl" + j;
lbl.Text = dtprice1.Rows[j]["Price"].ToString();
PriceTotal += Convert.ToDecimal(dtprice1.Rows[j]["Price"]);
PlaceHolderPrice.Controls.Add(lbl);
PlaceHolderPrice.Controls.Add(new LiteralControl("<br />"));
}
else if (Convert.ToInt32(dayofweek) == Convert.ToInt32(date.DayOfWeek + 1))
{
lbl.ID = "lbl" + j;
lbl.Text = dtprice1.Rows[j]["Price"].ToString();
PriceTotal += Convert.ToDecimal(dtprice1.Rows[j]["Price"]);
PlaceHolderPrice.Controls.Add(lbl);
PlaceHolderPrice.Controls.Add(new LiteralControl("<br />"));
}
}
}
else
{
DataView dv1 = new DataView(dtprice);
dv1.RowFilter = "PriceStartDate IS NULL OR PriceEndDate IS NULL";
//dv1.RowFilter = "PriceStartDate == null and PriceEndDate == null";
DataTable dtprice2 = new DataTable();
dtprice2 = dv1.ToTable();
for (int j = 0; j < dtprice2.Rows.Count; j++)
{
Label lbl = new Label();
string dayofweek = dtprice2.Rows[j]["DayOfWeekId"].ToString();
if (dayofweek.Trim() == eDayOfWeek.All.ToString().Trim())
{
lbl.ID = "lbl" + j;
lbl.Text = dtprice2.Rows[j]["Price"].ToString();
PriceTotal += Convert.ToDecimal(dtprice2.Rows[j]["Price"]);
PlaceHolderPrice.Controls.Add(lbl);
PlaceHolderPrice.Controls.Add(new LiteralControl("<br />"));
}
else if (Convert.ToInt32(dayofweek) == Convert.ToInt32(date.DayOfWeek + 1))
{
lbl.ID = "lbl" + j;
lbl.Text = dtprice2.Rows[j]["Price"].ToString();
PriceTotal += Convert.ToDecimal(dtprice2.Rows[j]["Price"]);
PlaceHolderPrice.Controls.Add(lbl);
PlaceHolderPrice.Controls.Add(new LiteralControl("<br />"));
}
}
}
}
}
}
lbldipositamount.Text = PriceTotal.ToString();
// var amount = ((System.Data.DataRowView)(e.Item.DataItem)).Row.ItemArray[3];
int selectedvalue = Convert.ToInt32(ddlList.SelectedItem.Text);
if (selectedvalue != 0)
{
double totalamount = selectedvalue * Convert.ToDouble(PriceTotal);
lbldipositamount.Text = totalamount.ToString();
}
}
}
catch (Exception)
{
throw;
}
}
On dynamically genereted dropdown selection event fired
In above even add this dropdown dynamically, now when this control's event is called , further dynamic control is adding as per the condition.
Issue is this event remove the dynamic other control as well even for other row of the previous selection is hidden or lost , so we retain the dynamic control in any post back and event fire.
protected void ddlAvailable_SelectedIndexChanged(object sender, EventArgs e)
{
// if (UserControlTextBoxChanged != null) dlLodgingAvailableDetails_ItemDataBound(sender, e);
//dlLodgingAvailableDetails.ItemDataBound += new DataListItemEventHandler(dlLodgingAvailableDetails_ItemDataBound);
double amount = 0;
var ddlList = (DropDownList)sender;
var row = (DataListItem)ddlList.NamingContainer;
//get the Id of the row
DataSet ds = new DataSet();
int? Id = Convert.ToInt32(((HiddenField)row.FindControl("hdnItemTypeId")).Value);
double? tamount = Convert.ToDouble(((Label)row.FindControl("lblTotalAmount")).Text);
int? groupid = Convert.ToInt32(ddlLodgingGroup.SelectedValue);
int selectedvalue = Convert.ToInt32(ddlList.SelectedItem.Text);
DateTime? startdate = Convert.ToDateTime(txtFromDate.Text);
DateTime? enddate = Convert.ToDateTime(txtToDate.Text);
ds = LodgingData.SelectLodgingItemTypeDataSet(startdate, enddate, groupid);
DataTable dt = new DataTable();
DataView dv = new DataView();
if (ds != null)
{
dt = ds.Tables[0];
dv = dt.DefaultView;
dv.RowFilter = "LodgingItemTypeId=" + Id;
}
dt = dv.ToTable();
if (dt.Rows.Count > 0)
{
if (tamount != null)
{
amount = Convert.ToDouble(tamount);
}
}
//amount = Convert.ToDouble(((Label)row.FindControl("lblTotalAmount")).Text);
var PlaceHolder1 = ((PlaceHolder)row.FindControl("PlaceHolderAdult"));
double totalamount = 0;
if (selectedvalue != 0)
{
totalamount = selectedvalue * Convert.ToDouble(amount);
((Label)row.FindControl("lblTotalAmount")).Text = totalamount.ToString();
Label lblAdult = new Label();
lblAdult.ID = "lblAdult";
lblAdult.Text = "Adult";
lblAdult.Font.Bold = true;
PlaceHolder1.Controls.Add(lblAdult);
PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
}
else
{
totalamount = amount;
}
for (int j = 0; j < selectedvalue; j++)
{
DropDownList ComboBox = new DropDownList();
ComboBox.ID = "ComboBox" + j;
ComboBox.AutoPostBack = false;
ComboBox.Attributes.Add("runat", "server");
ComboBox.Items.Add(new ListItem("0", "0"));
ComboBox.Items.Add(new ListItem("1", "1"));
ComboBox.Items.Add(new ListItem("2", "2"));
ComboBox.SelectedIndexChanged += new EventHandler(Dynamic_Method);
PlaceHolder1.Controls.Add(ComboBox);
PlaceHolder1.Controls.Add(new LiteralControl("<br />"));
}
}
I'm not sure how much this will solve for you, but here is an example of preserving a row of data in a gridview with a templatefield containing a dynamically generated dropdownlist
I broke the process into 2 parts
1) Save data currently in Gridview to a session variable
2) Recreate, source, and bind controls
Here's saving the values in the gridview. I use a recursive find control formula I found on this site (but don't remember from where) because my controls are generated and placed inside the gridview row without unique names. For ex. the tbxA that exists in row 1 is different than the tbxA in row 2. This may not apply to you - the key is to find all controls you want to save the values of.
Private Sub SaveValues()
Dim savedTable As New DataTable
savedTable.Columns.Add(New DataColumn("A"))
For i = 0 To GridView1.Rows.Count - 1
Dim existing(0) As Object
existing(0) = TryCast(FindControlRecursive(GridView1.Rows(i), "ddlA"), DropDownList).SelectedValue
savedTable.Rows.Add(existing)
Next
Session("GhostTable") = savedTable
End Sub
Then in Page_Load under(when it IS a postback) set the gridview datasource to the session variable, and databind it. This will trigger the following code for every row:
Keep in mind I also have the datasource of the dropdown list stored in a session variable on page load. This allows the datasource and databind to occur for the dropdown every time it is generated.
Protected Sub OnRowDataBound(sender As Object, e As GridViewRowEventArgs) Handles GridView1.RowDataBound
'Handles databinding of each gridview1 row ddl to gridview templatefield
If e.Row.RowType = DataControlRowType.DataRow Then
Dim ddlA As New DropDownList()
ddlA.DataSource = Session("lengthList")
ddlA.DataBind()
ddlA.ID = "ddlA"
ddlA.SelectedValue = TryCast(e.Row.DataItem, DataRowView).Row.Item("A").ToString()
e.Row.Cells(1).Controls.Add(ddlA)
End if
End Sub
The ddlA.SelectedValue = TryCast(e.Row.DataItem, DataRowView).Row.Item("A").ToString() is what preserves the data after any postback. It determines which row is being bound, and then repopulates the control with whatever it previously was.
Hope this helps!
To make sure that the gridview is populated every time, call SaveValues in your event handlers.
Protected Sub ddlEmpNumber_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ddlEmpNumber.SelectedIndexChanged
'Do whatever on selected index change, then the following:
Call SaveValues()
GridView1.DataSource = Session("GhostTable")
GridView1.DataBind()
End Sub
Do it all in the page_init
You're wiring up the eventhandler in the ASP part like this:
<asp:DataList ID ... OnSelectedIndexChanged="dlLodgingAvailableDetails_SelectedIndexChanged" ...
and then in code of the handler attempting to re-wire the other ones:
ComboBox.SelectedIndexChanged += new EventHandler(Dynamic_Method);
Any time you do dynamic stuff on a webforms page, all setup including event handler wireup must be in the page_init. When events run, re-wiring won't work. For what you're doing (asp: ... and during a method call), it's ending up in the wrong part of the lifecycle and the right things aren't there to either add the javascript to call doPostback, or if that runs the __eventargs, etc. have data for controls that aren't built yet (event postbacks are checked for AFTER page init so you have to create the controls before that check) and therefore get ignored.
Note - probably you know this but you have to give controls unique IDs, generally can by done if you have a numeric primary key by just appending to the datarows. (might have to do this manually to child controls in user control, have had to do this with usercontrols in page_init, hopefully you won't)
I work on a big app that dynamically builds every screen in webforms (from a UI generator) in the page-init. All work is done in events, they work like a charm! Page_load is basically empty. Get to know the asp page lifecycle - it's a booger but easier than rewriting your app in HotTowel (although think about that the next app ;-)
Pretty good diagram: http://blogs.msdn.com/b/aspnetue/archive/2010/01/14/asp-net-page-life-cycle-diagram.aspx
Good luck!
I have done every thing as above suggested and other google search site too. But it refresh the data and every time it rebind all dynamic object in the grid.
Finally I have done every thing based on javascript and jquery, without that dynamic control always rebind which I don't want. So any body who are stuck in this situation forgot to r and d and work with javascript/ webmethod with dynamic controls.
Thank all who given an answer
I am using a Gridview with datasource is a List. How can I show the header if the List is null or for a empty gridview?
if you are using fx4.0 then Set ShowHeaderWhenEmpty to true in Grid view
please look at below code
asp:GridView ID="gvPreview" runat="server" ShowHeaderWhenEmpty="True"
See A more elegant solution to display GridView header and footer when the data source is empty.
You can use HeaderTemplate property to setup the head programatically or use ListView instead if you are using .NET 3.5.
or
You can even try below
//if data exists
if (dtSource.Rows.Count != 0)
{
grdView.DataSource = dtSource;
grdView.DataBind();
}
else
{
//Other wise add a emtpy "New Row" to the datatable and then hide it after binding.
dtFunding.Rows.Add(dtSource.NewRow());
grdView.DataSource = dtSource;
grdView.DataBind();
grdView.Rows[0].Visible = false;
}