I'm relatively new to using VB, and am trying to do the following:
Select DropDownList item upon Button click
Link DropDownList items to internal pages
I feel like this is basic stuff, but am having a hard time with it.
Is this correct?
1 .
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True">
<asp:ListItem Value="Answer.aspx">Answer</asp:ListItem>
2 .
<asp:Button ID="Button1" runat="server" Text="Button" onselectedindexchanged="DropDownList1_SelectedIndexChanged" />`
You will need to change your code a little bit to achieve this. First, you do not need the AutoPostback on the dropdown list unless you want it to hit the server when you select a new list item.
On the button click, you will want to remove the
OnSelectedIndexChange="DropDownList1_SelectedIndexChanged"
And replace it instead with the button's OnClick event.
OnClick = "Button1_Click"
You will need to add your vb code to redirect to the new page. I'm more of a C# guy, but this should work.
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs)
Dim LinkText as string
LinkText = DropdownList1.SelectedItem.Value
Response.Redirect(LinkText)
End Sub
Are you trying to say, after clicking the button, it will go to the other page by selecting in dropdownlist what page it is? If I'm correct, here's how it is.
Private Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
Response.Redirect(DropDownList1.SelectedValue.ToString)
End Sub
Related
I have a method "Grid Batch Update", in this case, i want get an id from button clicked in this method
Private Sub grid_BatchUpdate(ByVal sender As Object, ByVal e As DevExpress.Web.Data.ASPxDataBatchUpdateEventArgs) Handles grid.BatchUpdate
'My Code
End Sub
I have tried to search but not found the answer
Ok, then as a general rule, you can use "sender".
Protected Sub Button1_Click1(sender As Object, e As EventArgs) Handles Button1.Click
Dim btn As Button = sender
Debug.Print("id of button is " & btn.ID)
End Sub
However, do note if you going to have say several buttions use the SAME event?
Then you should remove the handles from above. And then you "must" then set the on-click event.
So, above becomes:
Protected Sub Button1_Click1(sender As Object, e As EventArgs)
Dim btn As Button = sender
Debug.Print("id of button is " & btn.ID)
End Sub
And I might then say have two buttons use the same click event. eg this:
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click1" />
<br />
<asp:Button ID="Button2" runat="server" Text="Button" OnClick="Button1_Click1" />
So, if you double click on a button from the web forms designer, it will NOT put in a OnClick tag, but uses the "handles button one in code behind.
Either way is fine - but you don't need (nor want) the "handles" tied to one button on the code behind - so use markup OnClick="Button1_Click1"
In above, then clicking on either button would result in this:
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 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 am having a strange day! I am trying to access values inside the Datagrid control. There are textboxes in each row of the Datagrid control. If I use a asp.net button control outside the datagrid control I can access all the values. But if I use LinkButton outside the datagrid control then I cannot access any value.
I have to use LinkButton.
UPDATE 1: Code
//This works
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim indexes() As Integer = dgReceipts.SelectedIndexNumbers
End Sub
//This does not work and I get 0 items in the SelectedIndexNumbers
Protected Sub LinkButtonUpdateReceipts_Click(sender As Object, e As EventArgs) Handles LinkButtonUpdateReceipts.Click
Dim indexes() As Integer = dgReceipts.SelectedIndexNumbers
End Sub
<asp:Button ID="Button1" runat="server" Text="Button" />
<c1:LinkButton ID="LinkButtonUpdateReceipts" runat="server" Text="Update Totals" Icon="images/go-blue-right.gif"></c1:LinkButton>
I'm suprised that either of those work. You do not appear to have an OnClick event for either of those buttons. At a minimum I would add an OnClick event to your LinkButton that fires LinkButtonUpdateReceipts_Click.
Also, why aren't you just using <asp:LinkButton? what is <c1:LinkButton?
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;