The problem when loading a web user control dynamicly - asp.net

Question

The web user control: FilterLabel
<span style=" display:block; float:left; margin:5px; padding: 5px; border: 1px inset #000000; font-family: Tahoma; font-size: small;">
<asp:Label ID="lblFilterDisplay" runat="server" Text="Product/Service: This is a testing"></asp:Label>
<asp:ImageButton ID="btnRemove" runat="server" ImageUrl="~/Images/remove.png" OnClick="btnRemove_Click" />
And the part of behind codes for this web user control:
public event EventHandler RemoveClick;
......
public void btnRemove_Click(object sender, EventArgs e)
{
if (RemoveClick != null)
RemoveClick(this, EventArgs.Empty);
}
Next, the web user control "FilterLabel" will be used in another web user control "FilterList":
<%# Register TagPrefix="uc" TagName="FilterLabel" Src="~/Controls/FilterLabel.ascx" %>
<asp:Panel ID="FilterList" runat="server" Width="100%" GroupingText="Filter List" CssClass="filterList">
</asp:Panel>
And the part of behind codes of this web user control is:
protected override void OnInit(EventArgs e)
{
if (IsPostBack)
{
BindFilters();
}
}
public void BindFilters()
{
List<FilterLabel> filters = Filters;
foreach (FilterLabel filter in filters)
{
FilterList.Controls.Add(filter);
}
}
public List<FilterLabel> Filters
{
get
{
List<FilterLabel> filters = Session["Filters"] as List<FilterLabel>;
if (filters == null)
{
filters = new List<FilterLabel>();
}
return filters;
}
}
public void AddFilter(string filterName, string filterContent, string filterValue = null)
{
FilterLabel filter = LoadControl("~/Controls/FilterLabel.ascx") as FilterLabel;
filter.ID = "Filter";
filter.FilterContent = filterContent;
filter.FilterName = filterName;
filter.Value = filterValue;
filter.RemoveClick += new EventHandler(RemoveFilter);
List<FilterLabel> filters = Filters;
filters.Add(filter);
Session["Filters"] = filters;
BindFilters();
}
private void RemoveFilter(object sender, EventArgs e)
{
//some handling codes
}
So now the problem is the btnRemove_Click event isn't activated when I click the image button "btnRemove".

Answer 1

You should try with bubble event. with your solution you will need on each postback to rebind event handler on each usercontrol for existing filters
public int FilterCount
{
get{
if(ViewState["filter_count"] == 0){
FilterCount = 0;
}
return (int)ViewState["filter_count"];
}
set{
ViewState["filter_count"] = value;
}
}
protected void RecreateFilterControlls()
{
for(int i =0; i < FilterCount; i++){
FilterLabel filter = LoadControl("~/Controls/FilterLabel.ascx") as FilterLabel;
FilterList.Controls.Add(filter);
filter.RemoveClick += new EventHandler(RemoveFilter);
}
}
protected override void OnInit(EventArgs e)
{
if (IsPostBack)
{
RecreateFilterControlls();
}
}
// this is for button which will add new FilterLabel UserControl
protected void AddNewFilter_Click(object sender, EventArgs e)
{
// just create filter
AddFilter(<FilterNameTextBox|combobox>, <FilterContentTextBox>, <filterValue>);
}
public void AddFilter(string filterName, string filterContent, string filterValue = null)
{
FilterLabel filter = LoadControl("~/Controls/FilterLabel.ascx") as FilterLabel;
filter.ID = "Filter";
filter.FilterContent = filterContent;
filter.FilterName = filterName;
filter.Value = filterValue;
filter.RemoveClick += new EventHandler(RemoveFilter);
// increament filter count
FilterCount++;
}
private void RemoveFilter(object sender, EventArgs e)
{
//some handling codes
//remove control which caused this event
FilterList.Controls.Remove(sender); // or you will need to ask for IndexOf(sender);
FilterCount--;
}
the rest will be handled by ViewState it self, so you don't need to bind data back to FilterLabel back