ITemplate and linkbutton click event - asp.net

In my user control I have gridview, and this grid is created programmatically, using Itemplate. In InstantiateIn methods I have this code.
Select Case _templateType
Case ListItemType.Header
Dim linkButton As New LinkButton
linkButton.Text = "Delete"
linkButton.CommandName = "Click"
linkButton.CommandArgument = Me._columnID
container.Controls.Add(linkButton)
I want to wired up Click event to this LinkButton, and use this event in code behind.
This is constructor of GridViewTemplate how implements ITemplate
Public Sub New(ByVal type As ListItemType, ByVal colname As String, Optional ByVal infoType As String = "")
'Stores the template type.
_templateType = type
'Stores the column name.
_columnName = colname
_infoType = infoType
_columnID = columID
End Sub
and i have this call from user control:
bfield.ItemTemplate = New GridViewTemplate(ListItemType.Item, dt.Columns(col).ColumnName, "label")
where is
Dim bfield As TemplateField = New TemplateField()

AddHandler linkbutton.Click, AddressOf X 'X being the method that handles the click event.

AddHandler linkButton.Click, AddressOf linkButton_Click
Sub linkButton_Click(ByVal sender As System.Object, ByVal e As EventArgs)
' here is your click handler
End Sub

Related

How do i give a value a TextBox create dynamically when i click and doubleClick? vb.net

I have text box create like that:
Dim Result1 As New TextBox
Result1.ID = "BOX_Result" & a & "_" & i
I want when i click on that textbox to write "OK" and when i double click in cell to put NOT/OK
Important! The TextBox is created Dynamically if i try Result.Click doesn't work, get ne that error: "Result1.Click display error: "Click is not an event of 'System.Web.UI.WebControls.TextBox' "
I try like that but doesn't work:
AddHandler Result1.Click, AddressOf Me.Result1_Click
Private Sub Result1_Click(ByVal sender As Object, _
ByVal e As System.EventArgs)
Result1.Text = "OK"
End Sub
I want when a person click on that textbox created dynamically but doesn't work click. Thanks for help
You can add these lines to your TextBox definition:
Result1.Attributes.Add("onclick", "this.value = 'OK';")
Result1.Attributes.Add("ondblclick", "this.value = 'NOT/OK';")
In this code, the text "NOT/OK" is displayed when the user double-clicks in the TextBox. In your question, you talk about a double-click "in cell". If that "cell" is not the TextBox, please give some indication of what kind of control it is.
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim tb As New TextBox 'Create the new TextBox
AddHandler tb.DoubleClick, AddressOf TB_DoubleClick 'Add a handler to the textbox`s DoubleClick event
AddHandler tb.Click, AddressOf TB_Click
'Set any other properties of textbox you want here....
Me.Controls.Add(tb) 'Add the textbox to the forms controls
End Sub
'This is the textbox Click event handler sub
Private Sub TB_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim tb As TextBox = DirectCast(sender, TextBox) 'Cast the (sender) into a textbox to get access to the textbox`s properties
Result1.Text = "OK"
End Sub
'This is the textbox DoubleClick event handler sub
Private Sub TB_DoubleClick(ByVal sender As Object, ByVal e As System.EventArgs)
Dim tb As TextBox = DirectCast(sender, TextBox) 'Cast the (sender) into a textbox to get access to the textbox`s properties
Result1.Text = "NOT OK"
End Sub
I have create a simple exemple for you :
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim Result1 As New TextBox
Result1.Text = "BOX_Result"
Dim loc As New Point With {.Y = 117, .X = 111}
Result1.Location = loc
Me.Controls.Add(Result1)
AddHandler Result1.Click, AddressOf Me.Result1_Click
End Sub
Private Sub Result1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim txt As TextBox = sender
sender.Text = "OK"
End Sub
End Class
Hope that you want

Gridview rowcommand event not firing in dynamically added usercontrol

I have a usercontrol with gridview and rowcommand event.
This usercontrol is added dynamically using LoadControl on a button click of a page. The gridview's rowcommand doesn't fire.
Here is the code that loads the usercontrol on button click:
Protected Sub btnSearch_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnSearch.Click
'<ucTitle:SearchList ID="ucSearchList" runat="server" Visible="false" />
Dim ucSearchList As TitleSearchList = LoadControl("~/Controls/TitleSearchList.ascx")
ucSearchList.ISBN = txtSearchISBN.Text
ucSearchList.LoadTitleSearchList()
pnlSearchResults.Controls.Add(ucSearchList)
End Sub
And here is the code in usercontrol
Public Class TitleSearchList
Inherits System.Web.UI.UserControl
Public Property ISBN As String
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
If Not IsPostBack Then
LoadTitleSearchList()
End If
End Sub
Public Sub LoadTitleSearchList()
Dim _isbn As String = ISBN
Dim titles As New List(Of Title)
titles = New List(Of Title) From {
New Title With {.ISBN = _isbn, .TitleName = "Title check"},
New Title With {.ISBN = _isbn, .TitleName = "Title check"},
New Title With {.ISBN = _isbn, .TitleName = "Title check"},
New Title With {.ISBN = _isbn, .TitleName = "Title check"}
}
gvTitle.DataSource = titles
gvTitle.DataBind()
End Sub
Public Sub gvTitle_Rowcommand(ByVal sender As Object, ByVal e As GridViewCommandEventArgs) Handles gvTitle.RowCommand
If e.CommandName = "TitleDetail" Then
Response.Redirect("TitleSearch.aspx?isbn=" & e.CommandArgument().ToString())
End If
End Sub
End Class
Events in GridViews that are added dynamically in a UserControl get a little ugly. Since UserControls that are added dynamically have to be re-added on the post-back, you have to rebind the GridView DataSource, which makes you lose out on automatically getting those Events fired for you. That being said, you can still pull it off with some parsing of the __EVENTTARGET of the Form.
Add a HiddenField that tells you whether or not you need to re-add the UserControl. Add this in your Page_Load Event Handler:
If CBool(hdnTitleSearchActive.Value) = True Then
AddSearchListToPanel()
End If
Call AddSearchListToPanel() in your btnSearch_Click Event Handler.
Now this implementation of AddSearchListToPanel can be cleaned up some, but this should be good enough to get you going. Note that the Button triggering the GridView Command in my example has the ID of lbtTest. You will have to adjust based on the ID that you are using.
Private Sub AddSearchListToPanel()
Dim ucSearchList As TitleSearchList = LoadControl("~/Controls/TitleSearchList.ascx")
ucSearchList.ISBN = txtSearchISBN.Text
ucSearchList.LoadTitleSearchList()
pnlSearchResults.Controls.Add(ucSearchList)
hdnTitleSearchActive.Value = True
Dim strEventTarget As String = HttpContext.Current.Request.Form("__EVENTTARGET")
If Not strEventTarget Is Nothing AndAlso strEventTarget.Contains("gvTitle$") AndAlso _
strEventTarget.Contains("$lbtTest") Then
'Value example = gvTitle$ctl02$lbtTest
Dim intRowNumber As Integer = (CInt(strEventTarget.Substring(11, 2)) - 1)
Dim lbtCommandSource As LinkButton = CType(CType(ucSearchList.FindControl("gvTitle"), GridView).Rows(intRowNumber).FindControl("lbtTest"), LinkButton)
Dim objCommandEventArguments As New CommandEventArgs(lbtCommandSource.CommandName, lbtCommandSource.CommandArgument)
Dim objGridViewCommandEventArgs As New GridViewCommandEventArgs(lbtCommandSource, objCommandEventArguments)
ucSearchList.gvTitle_Rowcommand(lbtCommandSource, objGridViewCommandEventArgs)
End If
End Sub

Asp.Net Null Reference Exception on Event Handler for Dynamic Controls

I've created some dynamic controls on page load and added an event handler to handle the click event of a dynamic link button. Within the sub of the click event handler, I need to reference some other (non-dynamic) controls on the page and change their value. However, I get a null reference exception - object not set to an instance of an object - each time I try to reference a control on the page (in this case label1). What am I doing wrong in creating these dynamic controls or with my event handler? Thanks!
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
'Get the data to populate the controls
Dim oMySqlData As New MySqlDataProvider
PlaceHolder1.Controls.Add(CreateExistingNotesHTML(oMySqlData.GetParentNotes("104628"), oMySqlData.GetChildNotes("104628")))
End Sub
Public Sub OnCommentClick(ByVal sender As Object, ByVal e As EventArgs)
'The event handler for the link buttons
Label1.Text = "You clicked " & DirectCast(sender, LinkButton).ID
End Sub
Public Function CreateExistingNotesHTML(ByVal dtParent As DataTable, ByVal dtChild As DataTable) As HtmlGenericControl
'The routine that creates the dynamic controls
Dim divContainer As New HtmlGenericControl("div")
For Each drParent As DataRow In dtParent.Rows()
divContainer.Controls.Add(WriteNote(drParent.Item("NoteId").ToString(), drParent.Item("UserName").ToString(), drParent.Item("ItemNote").ToString, CDate(drParent.Item("InsertDate")), "note"))
Next
Return divContainer
End Function
Private Function WriteNote(ByVal NoteId As String, ByVal UserName As String, ByVal ItemNote As String, ByVal InsertDate As DateTime, ByVal DivClass As String) As HtmlGenericControl
Dim div As New HtmlGenericControl("div")
div.ID = "d" & NoteId
div.Attributes.Add("class", DivClass)
div.Controls.Add(New LiteralControl(" ยท "))
'Add the dynamic link buttons
Dim lnkComment As New LinkButton
lnkComment.ID = "l" & NoteId
lnkComment.Text = "Comment"
lnkComment.Style("Text-decoration") = "none"
AddHandler lnkComment.Click, AddressOf oNotes.OnCommentClick
div.Controls.Add(lnkComment)
Return div
End Function
With this line
Dim oNotes As New EbayItemNotes
AddHandler lnkComment.Click, AddressOf oNotes.OnCommentClick
You are handling this event outside of your page and within the EbayItemNotes class, how does this class know anything of Label1 that resides in your page?
Could it be that you need to pass your label in as well..
Dim oNotes As EbayItemNotes = new EbayItemNotes(label1)
inside EbayItemNotes constructor
public sub New(lbl as Label) //store this label for use in event handler..

re-add your handler on every postback

when the page is loaded the following code is invoke
page load
Dim products As New LinkButton
products.Text = "Products"
testPanel.Controls.Add(products)
AddHandler products.Click, AddressOf getProducts
getProducts function
Dim testDb As New Product
Dim arr As ArrayList = testDb.DbLoop()
Dim ObjList As ProductBo
Dim ID As Integer
Dim link As LinkButton
For Each ObjtList In arr
ID= ObjtList.C_Id
link = New LinkButton
testPanel.Controls.Add(New LiteralControl("<br />"))
link.ID = ID
link.Text = ObjList.Name
link.CommandArgument = CustInt
Me.testPanel.Controls.Add(link)
AddHandler link.Click, AddressOf getProductsDetails
Next ObjList
what i want to achive when the page load i link is create Products when i click on products link it invoke an event handler call getProducts. getproducts will loop in the database to fetch all record then it will creat a link for each product name when i click on the product name it should invoke another event. my problem is how can i re add control after every postback thank u
Because the links are dynamically created, you have to re-create and re-add the handler for them on each postback.
On the _init event, you have to check the state you are in (before product load or after product load), then create either the Product Load link OR the Product Details link. Key is they have to be created EVERY postback AND they have to be created before the _Load event. Typically this should be done on the _Init event.
Something along the lines of this:
Private Sub Page_Init(sender As Object, e As System.EventArgs) Handles Me.Init
If ViewState.Item("ProductsLoaded") IsNot Nothing Then
If ViewState.Item("ProductsLoaded").ToString = "True" Then
GetProducts(Me, New EventArgs)
Else
CreateProductsButton()
End If
Else
CreateProductsButton()
End If
End Sub
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
End Sub
Private Sub CreateProductsButton()
Dim btnProducts As New LinkButton
btnProducts.Text = "Products"
testPanel.Controls.Add(btnProducts)
AddHandler btnProducts.Click, AddressOf GetProducts
ViewState.Item("ProductsLoaded") = False.ToString
End Sub
Private Sub GetProducts(sender As Object, e As EventArgs)
' get products list here
' and set handlers for each link
ViewState.Item("ProductsLoaded") = True.ToString
End Sub
Private Sub GetProductsDetails(sender As Object, e As EventArgs)
'get product details here
End Sub

Dynamic link button not firing in update panel

I'm dynamically adding a link button in the footer of a grid view. The grid view is wrapped in an update panel. I can get an async post back (I can tell by seeing an update progress flash), but I can't get the debug point in my click function to fire.
Private Sub gvParts_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvParts.RowDataBound
ElseIf e.Row.RowType = DataControlRowType.Footer Then
If _showPrice Then
Dim clearbutton As New LinkButton
clearbutton.ID = "btnClearCart"
clearbutton.Text = "Remove All"
ScriptManager1.RegisterAsyncPostBackControl(clearbutton)
e.Row.Cells(7).Controls.Add(clearbutton)
AddHandler clearbutton.Command, AddressOf clearButton_click
End If
End If
Private Sub clearButton_click(ByVal sender As Object, ByVal e As System.EventArgs)
ClearCart()
End Sub
try this
<dl>
Private Sub gvParts_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvParts.RowDataBound
ElseIf e.Row.RowType = DataControlRowType.Footer Then
If _showPrice Then
Dim clearbutton As New LinkButton
clearbutton.ID = "btnClearCart"
clearbutton.Text = "Remove All"
ScriptManager1.RegisterAsyncPostBackControl(clearbutton)
e.Row.Cells(7).Controls.Add(clearbutton)
AddHandler clearbutton.Command, AddressOf clearButton_click
ScriptManager.GetCurrent(Me).RegisterAsyncPostBackControl(clearbutton)
End If
End If
Sorry,It's my mistake I have posted wrong code.Place the above code on OnRowCreated event of gridview
try this
Private Sub gvParts_RowCreated(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles gvParts.RowDataBound
ElseIf e.Row.RowType = DataControlRowType.Footer Then
If _showPrice Then
Dim clearbutton As New LinkButton
clearbutton.ID = "btnClearCart"
clearbutton.Text = "Remove All"
ScriptManager1.RegisterAsyncPostBackControl(clearbutton)
e.Row.Cells(7).Controls.Add(clearbutton)
AddHandler clearbutton.Command, AddressOf clearButton_click
ScriptManager.GetCurrent(Me).RegisterAsyncPostBackControl(clearbutton)
End If
End If
The controls have to be added to your Controls collection prior to the page_load event. The default databinding (which fires the OnRowCreated, OnRowDataBound events) happens during the OnLoad event. Try moving your databinding code to the Page_Init function. Depending on what your databinding code looks like, this might mean you will have to implement the databinding "manually" (ie. Set the datasource and call .DataBind() in code)

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