Here is my drop down list and data source. My question is.. when is it possible to set a defaulted selected option for the drop down list, aka when have all the dropdownlists been databound and their ListItems populated? I have tried Page_PreRender, Page_PreRenderComplete, Page_Load.
I have read over MSDN's Page Life cycle event which suggest Page_PreRender.
<asp:DropDownList ID="ddlRampStandard" runat="server"
DataSourceID="RampStandardDataSource" DataTextField="StandardName"
DataValueField="StandardName" RepeatDirection="Horizontal"
ViewStateMode="Enabled"></asp:DropDownList>
<asp:SqlDataSource ID="RampStandardDataSource" runat="server"
ConnectionString="<%$ ConnectionStrings:AIMP_DeleteMeConnectionString %>"
SelectCommand="SELECT [StandardName] FROM [CR_Standard]"></asp:SqlDataSource>
Here's the simple code-behind which illustrates what I'm trying to do.
Protected Sub Page_PreRenderComplete(sender As Object, e As System.EventArgs) Handles Me.Load
ddllstSideOfStreet.Items(0).Selected = True
End Sub
I'm getting an instance not created error suggesting ddllstSideOfStreet has no items. I do verify that with a breakpoint and watch that there are no items in existence in any of the previously mentioned prerender, load, prerendercomplte functions.. However when the page loads, the dropdownlist does indeed load with the expected databound information. Thoughts?
just to make sure, have both the handler in the markup and the method using the correct handler in the code behind.
Like this:
Protected Sub Page_PreRender(sender As Object, e As System.EventArgs) Handles Me.PreRender
End Sub
And the markup as follows:
<asp:DropDownList ID="ddlRampStandard" runat="server"
DataSourceID="RampStandardDataSource" DataTextField="StandardName"
DataValueField="StandardName" RepeatDirection="Horizontal"
ViewStateMode="Enabled" OnPreRender="Page_PreRender"></asp:DropDownList>
Tried a similar solution on my machine a moment ago and it worked.
Related
I have encountered a problem with a page we have, and have narrowed down a sample like so:
ASPX:
<div>
<asp:DropDownList ID="ddlSomething" runat="server"
CausesValidation="true" AutoPostBack="true">
<asp:ListItem>One</asp:ListItem>
<asp:ListItem>Two</asp:ListItem>
</asp:DropDownList>
<asp:Button ID="btnFilter" runat="server" Text="Filter" />
</div>
Code:
Partial Class ValTest
Inherits System.Web.UI.Page
Protected Sub btnFilter_Click(sender As Object, e As EventArgs) Handles btnFilter.Click
BindGrid()
End Sub
Protected Sub ddlSomething_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ddlSomething.SelectedIndexChanged
BindGrid()
End Sub
Private Sub BindGrid()
If (Page.IsValid) Then
'Do something that takes a little time here
System.Threading.Thread.Sleep(2000)
Response.Write("Done")
End If
End Sub
End Class
Note that the dropdown list has autopostback set to true and causesvalidation set to true.
Now, if I change the dropdown list and let the page load, it works without issue. Similarly, if I just click the button, then it works ok. However, if I change the dropdown list and then, before the page has totally reloaded, click the button, then I get this error:
Page.IsValid cannot be called before validation has taken place. It should be queried in the event handler for a control that has CausesValidation=True and initiated the postback, or after a call to Page.Validate.
Now, I can fix this by putting a Page.Validate() in front of my check for Page.IsValid, however I am curious if anybody can explain why this is happening. I am expecting two postbacks to have been sent, each causing validation, and each should have worked...
ASP.net 4.5, just in case it makes a difference.
I have a data repeater that is binding to an ObjectDataSource on a page. I have the select working but I am having a problem with the Update. When I call a Save button what I want to do is call the function specified in the UpdateMethod and pass it in a parameter of the changed object of the repeater. Problem is I can't figure out how to get the object back out of the repeater. I do not want to specify each individual field as an update parameter as that is really unwieldy and defeats the purpose of data binding. Any help on this would be great.
<%# Page Language="VB" %>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<asp:Repeater ID="Repeater1" runat="server" DataSourceID="ObjectDataSource1" ItemType="CompanyObject">
<ItemTemplate>
<asp:Label ID="Label2" runat="server" CssClass="clsLabel">Company:</asp:Label>
<asp:TextBox ID="txtCompany" runat="server" Text='<%# BindItem.Company%>'></asp:TextBox>
</ItemTemplate>
</asp:Repeater>
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
SelectMethod="GetData" TypeName="WebApplication1.CompanyObject"
UpdateMethod="UpdateCompany" DataObjectTypeName="CompanyObject"></asp:ObjectDataSource>
</form>
</body>
</html>
Here is the code behind that I want to call:
Public Function UpdateCompany(ByVal company As tblCompany)
'Save the Value here except that company is always null
End Function
Private Sub btnSave_Click(sender As Object, e As EventArgs) Handles btnSave.Click
ObjectDataSource1.Update()
End Sub
You can't do that with a Repeater control: it doesn't keep a copy of the objects to which it was bound. It doesn't do two-way binding.
But other controls do. Check out the FormView, GridView, and DetailsView. For a full treatment of the subject, see here.
I'm not sure I completely follow what's going on here, and I don't have enough reputation to ask in a comment. Where is your save button? I'm guessing it's outside the repeater. Are you trying to save all the companies that appear in your repeater, or is there only one company anyway? What are you trying to get back out of the repeater? Just the company name that's in the textbox? A few more details may provide the help you're looking for.
Also, it might be helpful to add an OnUpdating event to your ObjectDataSource and handle that in your code behind.
<asp:ObjectDataSource ID="ObjectDataSource1" runat="server"
SelectMethod="GetData" TypeName="WebApplication1.CompanyObject"
UpdateMethod="UpdateCompany" DataObjectTypeName="CompanyObject"
OnUpdating="Company_Updating"></asp:ObjectDataSource>
And then your code behind:
Private Sub Company_Updating(ByVal s As Object, ByVal e As ObjectDataSourceMethodEventArgs)
' use e.InputParameters here to pass in the values you need
End Sub
You can see here for an example of how to use InputParameters.
Update
To answer your question, you should be able to use the following to get the value out of the textbox in the repeater:
Protected Sub Company_Updating(ByVal s As Object, ByVal e As ObjectDataSourceMethodEventArgs)
If (Repeater1.Items.Count > 0) Then
e.InputParameters.Add("CompanyName", CType(Repeater1.Items(0).FindControl("txtCompany"), TextBox).Text
End If
End Sub
But I think a repeater is unnecessary for what you're trying to do here. A repeater is generally used to show a collection of items. If your goal is to simply show one company, couldn't you set the Text property of the TextBox control in your code behind?
Protected Sub Page_Load(ByVal s As Object, ByVal e As EventArgs) Handles Me.Load
If (Not Page.IsPostBack) Then
txtCompany.Text = yourCompanyObject.Name
End If
End Sub
This is not possible with the approach you are following.
We can for sure develop a custom Post Back to achieve the desired output.
I have the following button:
<asp:ImageButton ID="imgbtnEditInfo" runat="server" ImageUrl="~/images/EditInformation.png" AlternateText="EditInformation" CommandName="EditDetails" CommandArgument="<%# Container.DataItemIndex %>" OnClick="lnkEdit_Click" Enabled="true" />
I have the following method but looks like it is not hitting the method:
Protected Sub lnkEdit_Click(ByVal sender As Object, ByVal e As System.EventArgs)
End Sub
Wondering if I am missing something. I put a breakpoint on the Protected Sub lnkEdit_Click but on click of the imagebutton I do not go there.
You're working with Data Controls (GridView or DataList etc). To respond to the button/linkbutton/imagebutton events, you must have to handle the parent - data control's events.
Without seeing more of your page it is hard to say. A couple things to check:
Is the ImageButton inside a <form runat="server">?
Have you compared your page to the VB sample at ImageButton Class to see if anything might have been missed?
I have an ASP.Net page, which displays a list of options to the user. When they select from the list, it does a post back and queries a sql server. The results are displayed in a listview below the options in an update panel. Below is a snippet of the ItemTemplate:
<asp:LinkButton Text="Save IT" OnCommand="SaveIt" CommandArgument="<%# Container.DataItemIndex %>" runat="server" />
The DataItemIndex does not appear, so my commandargument is empty. However, the object sender is the button, which shows the item.
Why is the index item not appearing in the CommandArgument?
Could it be the post back? If so, why would it be the post back? Is there a way around it?
Edit:
Sorry, from my attempts to solve it before, I posted bad code, but it still isn't appearing.
Resolution:
I found another work around in that the sender of the OnCommand is the link button, which has the CommandArgument. I will chalk this issue up to be an issue with multiple postbacks and javascript.
You can't use the <%= %> syntax inside properties on a tag with a runat="server" attribute. I'm surprised the code will even run. :)
UPDATE:
You probably want to use the ItemDataBound event on the repeater, find the linkbutton and set the CommandArgument property.
Not very elegant, but here's a VB.NET sample.
Private Sub Repeater1_ItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.RepeaterItemEventArgs) Handles Repeater1.ItemDataBound
Select Case e.Item.ItemType
Case ListItemType.Item, ListItemType.AlternatingItem
Dim b As LinkButton = e.Item.FindControl("btn")
b.CommandArgument = e.Item.ItemIndex
b.DataBind()
End Select
End Sub
You're not setting it
You possibly want
<%# Container.DataItemIndex %>
or
<%= Container.DataItemIndex %>
:)
Try
<asp:LinkButton Text="Save IT" OnCommand="SaveIt" CommandArgument="<%# Container.DataItemIndex %>" runat="server" />
You were missing the "#" sign.
This site really helped me with this problem: http://forums.asp.net/t/1671316.aspx
The issue I ran into was that I was being passed null arguments in the commandargument when I clicked on the button a second time. As the post above explains, this is because commandargument is only set in the databind event. So, to fix this, include a databind event in the page_load sub
Ex. (VB)
Private Sub BindSelectButtons()
'Purpose: bind the data to the select buttons for commandargument to be used
Dim i As Integer
For i = 0 To gridview1.Rows.Count - 1
gridview1.Rows(i).Cells(8).FindControl("btnID").DataBind()
Next
End Sub
Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
'Rebind select buttons so that the commandargument refreshes
BindSelectButtons()
End Sub
Make sure View State is enabled
e.Row.EnableViewState = true;
I want to access the data associated with the RepeaterItem in which an ItemCommand fired up. The scenario is, I have multiple RepeaterItems which Button controls in which the Command is set declaratively like this:
<asp:Repeater ID="Repeater3"
runat="server"
DataSource='<%# ClientManager.GetClientEmployees(Eval("ClientID")) %>'
OnItemCommand="RemoveEmployeeFromClient">
<ItemTemplate>
<asp:LinkButton ID="LinkButton1"
runat="server"
Text="(x)"
CommandName="RemoveEmployeeFromClient">
</asp:LinkButton>
</ItemTemplate>
<SeparatorTemplate>,<br /></SeparatorTemplate>
</asp:Repeater>
The code behind is:
Protected Sub RemoveEmployeeFromClient(ByVal source As Object,
ByVal e As RepeaterCommandEventArgs)
' I want to access the data associated with
' the RepeaterItem which the Button was clicked.
End Sub
You can use e.Item.DataItem to get down to the data for the object, or you could store it in a hidden field.
Building on what Mitchel said, make sure you check to see that the RowType is DataRow. Don't want to do crap when you can't. The cast from e.Item.DataItem to your type would fail on the header or footer row.