I have a custom control which contains a Repeater control. The Repeater has an ItemTemplate. Inside that item template I have a panel which is going to hide something based on "IsEditable" a boolean property of the custom control. What I would like to do is set the panel's visibility once before the Repeater is databound.
I know I could do an onItemDataBound event and use FindControl to get the panel but that seems a little excessive since it will always be either visible or not for all rows and I have no other actions that need to occur on databind.
Is there a way to find the control in the ItemTemplate before the Repeater is databound?
try this:
<ItemTemplate>
<asp:Panel Visible='<%# this.IsEditable %>' runat="server">
editableStuff
</asp:Panel>
</ItemTemplate>
Related
We are using ASP.NET for one of our projects. However, when we are trying to read the SelectedItem or SelectedValue property of the DropDownList we are using in the callback function of a Link click, we are not getting the correct SelectedItem.
<FooterTemplate>
<asp:DropDownList ID="cmbTesters" ClientIDMode="Static" runat="server" Width="300px" DataSource='<%# PopulateTesterNames() %>' DataTextField="FullName" DataValueField = "PK_ID"></asp:DropDownList>
</FooterTemplate>
This is the DropDownList in the aspx file. The drop down is present within a GridView's Footer Row. We are invoking the following set of code on clicking a link.
if (int.TryParse(((DropDownList)dgCreateCPRVerificationResponse.FooterRow.FindControl("cmbTesters")).SelectedValue, out TesterID))
{
TesterID = int.Parse(((DropDownList)dgCreateCPRVerificationResponse.FooterRow.FindControl("cmbTesters")).SelectedValue);
}
The problem we are facing is that whatever value we choose, the SelectedValue is always of the first item in the list. We are using REST based URL defined in the global.asax file. Also note that this is not built on any framework.
Please help as soon as possible
Make sure to put the binding methods of the dropdownlist and the gridview inside if (!IsPostBack)
I have a dropdownlist with autopostback enabled. and have a repeater where i populate checkboxes from database.
If i set the autopostback to true then when selecting a value checkboxes lose its value...
Any workarounds on this?
Here is the code :
<asp:DropDownList ID="dropdown" runat="server" class="pop" AutoPostBack="true" >
</asp:DropDownList>
<asp:Repeater ID="rptD" runat="server" >
<ItemTemplate>
<td valign="top" >
<input type="checkbox" class="al" />
</ItemTemplate>
</asp:Repeater>
I assume this is because you are DataBinding the Repeater not only if(!IsPostBack) but also on postbacks. Therefore the checked state will be overriden.
So do this in Page_Load(assuming C#):
if(!IsPostBack){
DataBindRepeater();
}
Whereas DataBindRepeater is a method that sets the DataSource property and DataBind the Repeater.
You might also want to use an ASP.NET Checkbox control instead of the html input type="checkbox". The checked state is reloaded only if it's a server WebControl that implements IPostBackDataHandler.
This sounds indicative of populating the checkboxes in Page_Load. Is that the case? If you're populating the controls in Page_Load then you'll want to wrap it in a conditional:
if (!IsPostBack)
{
// populate your controls from data
}
Otherwise, they'll get re-populated with each postback. When you have an autopostback or click a button or perform some other action on the page which initiates a postback, Page_Load is called before the event handler. So in effect, this is happening:
User navigates to the page
Page_Load clears and populates the checkboxes
User chooses an item in the DropDownList (triggering a postback)
Page_Load clears and populates the checkboxes
DropDownList autopostback handler is called
(On a side note... Please look into using AJAX for dynamic client-server interaction like this. Autopostback makes for a poor user experience, and as you're discovering also makes for a difficult development experience.)
I have a data class that I want to show in a list on one page and also alone in another page. I know how to do the first:
<asp:Repeater ID="ctrl" runat="server">
<ItemTemplate>
Here's the name: <asp:Literal runat="server" Text='<%# Eval("Name") %>' />
</ItemTemplate>
</asp:Repeater>
On the other page, I want to show exactly one instance, and I want to reuse the item template. Is there a control that I can bind to a single instance of this class, instead of a list which contains a single element?
You can use the same Repeater but with a DataSource of on specific record/instance.
You can also use FormView control.
The FormView control gives you the ability to work with a single record from a data source. The FormView control does not specify a pre-defined layout for displaying the record. Instead, you create a template containing controls to display individual fields from the record. For information about programming the FormView control, see FormView Class in the MSDN library.
I have a nested repeater set up but the child repeater control is not being recognised in the code behind. It's not even being added to the designer file. I've tried this on an aspx and an ascx page but both gives the same problem.
<asp:Repeater ID="RepeaterParent" runat="server">
<ItemTemplate>
<asp:Repeater ID="RepeaterChild" runat="server">
</asp:Repeater>
</ItemTemplate>
</asp:Repeater>
with this on the page the code behind only recognises the RepeaterParent but not RepeaterChild.
Can anyone help me out here?
Many thanks!
Like any other control that is used within a repeater (or template) control, you need to retrieve the control using FindControl.
So, in your item data bind event handler for the parent, you would do:
var childRepeater = RepeaterParent.FindControl("RepeaterChild") as Repeater;
The RepeaterChild will be accessible when you use FindControl("RepeaterChild") on the parent repeater I think. Can't remember the exact syntax.
Also note that the FindControl method will also take the context of the current item of the parent repeater, as the name you specify will repeat. Naming containers do some work in the background to provide unique naming, but it is hard to track sometimes.
I have a grid view that is data bound to a dataset. In a grid I have a column DefaultValue, which has three controls in it - a dropdownlist, a checkbox and a textbox. Depending on the data that is coming in it can switch to any of these controls. Everything is simple enough when we need just to display data - in gridview_prerender event I simply make one of the controls visible. The control is setup like following:
<asp:TemplateField HeaderText="Default Value" SortExpression="DefaultValue">
<ItemTemplate>
<asp:TextBox ID="txt_defaultValue_view" runat="server" Text='<%# Bind("DefaultValue") %>' Enabled ="false" />
<asp:DropDownList ID="ddl_defaultValue_view" runat="server" Enabled ="false" />
<asp:CheckBox ID="chk_defaultValue_view" runat="server" Enabled ="false" />
</ItemTemplate>
<EditItemTemplate>
<asp:TextBox ID="txt_defaultValue_edit" runat="server" Text='<%# Bind("DefaultValue") %>'/>
<asp:DropDownList ID="ddl_defaultValue_edit" runat="server" />
<asp:CheckBox ID="chk_defaultValue_edit" runat="server" />
</EditItemTemplate>
</asp:TemplateField>
My problem starts when I am in edit mode and I need to update the grid with new data. Since only the textbox control is databound, the RowUpdating event can only access data from the textbox column and all of my other data simply gets discarded. I also can't databind with checkbox and dropdownlist control, since they can get an invalid data type exception. So, does anyone know how can I update a column that has three different controls, where each of these three controls might have a valid data?
Thanks
First, i would switch visibility of the controls in RowDataBound of the Grid and not on PreRender, because it can only change on DataBinding and not on every postback.
You can there also bind the Dropdown to its datasource, change the checked-state of the Checkbox and set the Text-property of the Textbox according to the the Dataitem of the Row.
When you update you can find your controls with FindControl in RowUpdating and get their values(f.e. Dropdownlist.SelectedValue).
GridView has pair of events:
RowUpdating/RowUpdated
RowDeleting/RowDeleted
....
In your case your need RowUpdating - is called right before update is performed, So find in row expected control (saying checkbox) and make preparation before pass to database
As another way review possibility to use ObjectDataSource event Updating - it is usual way to specify parameters for query execution.