i want to get value from grid view text box in Text Change Event but error comes
Object refrence is not set of an instance of an Object
Protected Sub onDebitChange(ByVal sender As Object, ByVal e As EventArgs)
Dim a, b As Integer
With GridView3
Dim rows As Integer = .Rows.Count
For i As Integer = 0 To rows - 1
Dim txtDebit As TextBox = CType(GridView3.Rows(i).FindControl("TotalDebit"), TextBox)
a = Val(txtDebit.Text)
b += a
Next
DebitBalance.Text = b
End With
End Sub
i also had tried for each loop but error is same
please help
You need to put the name of the ItemTemplate control correctly, in onDebitChange method please fix the control name to "Debit" not "TotalDebit" only:
Dim txtDebit As TextBox = CType(GridView3.Rows(i).FindControl("Debit"), TextBox)
Hope this helps.
Related
I tried to write a code to assign a value when I change the DetailsView to insert mode. for example, I need to assign an ID in a field:
1- I converted the field to (edit template).
2- I give it a new id.
3- I used this code in a Button_Click as below :
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
DetailsView1.ChangeMode(DetailsViewMode.Insert)
Dim txt As TextBox
If DetailsView1.CurrentMode = DetailsViewMode.Insert Then
txtBox = DirectCast(DetailsView1.FindControl("TextBox1"), TextBox)
txtBox .Text = ViewState("932")
End If
End Sub
but when I clicked the button it gives me this error.
Object reference not set to an instance of an object.
any help please ?
i had created a text box control array using the following code, where the no.of controls are generated on the basics of the value selected from the combo box
Protected Sub DropDownList1_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles DropDownList1.SelectedIndexChanged
Dim lstTextBox = New List(Of TextBox)()
For i As Integer = 0 To DropDownList1.SelectedValue
for j as integer =0 to 3
Dim txtbx As New TextBox()
txtbx.ID = String.Format("txtbx{0}", j)
lstTextBox.Add(txtbx)
txtbx.Text = "sample text " & j
form1.Controls.Add(txtbx)
next
Next
Session("lstTextBox") = lstTextBox
End Sub
now i need to insert the value to the database on a single button click, here the code is
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
dim mysql as string
mysql="insert into mytable values("
Dim lstText = New List(Of TextBox)()
lstText = Session("lstTextBox")
For i As Integer = 0 To lstText.Count - 1
for j as integer =0 to 3
mysql= mysql & "'" & trim(lstText(j).Text) & "',"
next
'execute insert for each row with the mysql string
Next
End Sub
now the problem is: only the initial values in the text boxes are inserted to the database, the changes which i had made in the text boxes are not inserted to the database. ie, in session the initial values will not change on text change in the text box.
i need a solution for this problem for proceeding my work. so expert's kind attention please.. positive responses will be appreciated.
Am not sure about VB and as well as My Sql. But i can give you a some way to get rid off from Session
Try like this in DropDownList1_SelectedIndexChanged,
if(Session("lstTextBox"))==null
Session("lstTextBox") = lstTextBox
else
Session.Abandon()
Session("lstTextBox") = lstTextBox
Now you go can check whether session is updating or not. As well as you may get the result as you want. Please let me know the output.
I want to get the value of my textbox that I created dynamically when I click a button
I need to do this cause the value of my textbox is used for retrieve data from database
how could I achieved this thing??
the flow is Button click - creating textbox - filling textbox with value - Button Click - Get Text of textbox
here is my code to make the textbox
Protected Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
For i As Integer = 0 To 4
textbox = New TextBox With {.ID = "TextBox" & i}
plchld.Controls.Add(textbox)
Next
End Sub
I have tried something like this but the code didn't work
Protected Sub OkButton_Click(sender As Object, e As EventArgs) Handles OkButton.Click
Dim a(5) As String
For i As Integer = 0 To 4
a(i) = CType(plchld.FindControl("Textbox" & i), TextBox).Text
Next
End Sub
thanks in advance for any help
edit for the answer
I've found the way to solve this. I use request.form to get the value of my textbox.
Thanks for anyone that participating
Regards,
Julian
This is how I have done in my asp.net application.
Creating dynamic control
TextBox txtDate = new TextBox();
txtDate.EnableViewState = true;
txtDate.ID = "PreixValue" + 1;
txtDate.Text = "07 Feb 2014"
pnl.controls.add(txtdate);
To retrieve the value from that textbox
DateTime datefrom = DateTime.Now ;
for (int cnt = 0; cnt < Request.Form.Count; cnt++)
{
if (Request.Form.AllKeys[cnt].Contains("Prefixvalue"))
{
int ParamStartPoint = Request.Form.AllKeys[cnt].IndexOf("Prefix") + 4;
int ParamNameLength = Request.Form.AllKeys[cnt].Length - ParamStartPoint;
string[] ControlName = Request.Form.AllKeys[cnt].Substring(ParamStartPoint, ParamNameLength).Split('$');
if (ControlName[0] == "Date From")
{
datefrom = DateTime.Parse(Request.Form[cnt]);
//datefrom has value now
}
}
}
This is how I have done in my web application, but there may be other ways achieve this.
basically when you create Dynamic control in webform this will be available through Request.Form.
hope this helps you.
Protected Sub OkButton_Click(sender As Object, e As EventArgs) Handles OkButton.Click
Dim a(5) As String
For i As Integer = 0 To 4
Dim anotherObj As TextBox = Me.Controls.Item("Textbox" & i)
a(i) =anotherObj.Text
Next
The issue is that dynamic controls are lost on a postback so when the OkButton click event is handled, there is nothing inside your plchld control. You must recreate your controls with the same ID on postback if you want to retrieve the text in the textboxes.
Using your code, all you need to do is on postback determine if the textboxes were created and if so, recreate them.
Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
' Determine if the text boxes were created and if so, recreate them.
If CBool(ViewState("TextBoxesCreated")) Then
CreateTextBoxes()
End If
End Sub
Protected Sub Button1_Click(ByVal sender As Object, ByVal e As EventArgs) Handles Button1.Click
CreateTextBoxes()
ViewState("TextBoxesCreated") = True
End Sub
Private Sub CreateTextBoxes()
For i As Integer = 0 To 4
plchld.Controls.Add(New TextBox With {.ID = "TextBox" & i})
Next
End Sub
Protected Sub OkButton_Click(ByVal sender As Object, ByVal e As EventArgs) Handles OkButton.Click
Dim a(4) As String
For i As Integer = 0 To 4
a(i) = CType(plchld.FindControl("Textbox" & i), TextBox).Text
Next
End Sub
I don't know the full extent of what you are doing but I would suggest not creating them dynamically if you don't need to. Just show or hide the textboxes instead.
Reference: http://www.codeproject.com/Articles/3684/Retaining-State-for-Dynamically-Created-Controls-i
I have a template field with a button. I want to press the button and get the row Id so I can return the users selection. I have a regular select button which works fine but the user want the people who are not employee’s to hide the select button. I have this working but since it’s a template field it fires the RoW_command procedure and I cannot seem to get the row index since it is a template field and not the regular Select button. Or I cannot seem to name the Regular select button since it Command field does not have a Name or ID property?
Like I said this works hiding the template field called btnSelect
Private Sub GridView3_RowDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewRowEventArgs) Handles GridView3.RowDataBound
If e.Row.RowType = DataControlRowType.DataRow Then
If (DataBinder.Eval(e.Row.DataItem, "LegacyPersonType") <> "Employee") Then
e.Row.ForeColor = Drawing.Color.Black
e.Row.BackColor = Drawing.Color.Yellow ' This will make row back color yellow
e.Row.FindControl("btnSelect").Visible = False
Else
e.Row.ForeColor = Drawing.Color.Black
e.Row.BackColor = Drawing.Color.White ' the normal employees make white
End If
End If
End Sub
I need to find the Row index when I press btnSelect
Private Sub GridView3_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles GridView3.RowCommand
Dim index As Integer = Convert.ToInt32(e.CommandArgument) ‘ Error invalid
‘ in other words when pressing the tem-plate field there is no e.CommandArgument
‘But clicking the regular select there is
Dim row As GridViewRow = GridView3.Rows(index)
Session("EnterpriseID") = HttpUtility.HtmlDecode(GridView3.Rows(index).Cells(2).Text)
Dim EmployeeType As String = HttpUtility.HtmlDecode(GridView3.Rows(index).Cells(7).Text)
Dim CommonName As String = HttpUtility.HtmlDecode(GridView3.Rows(index).Cells(1).Text)
Dim EnterpriseID = HttpUtility.HtmlDecode(GridView3.Rows(index).Cells(6).Text)
The GridViewRow object knows its row index via the RowIndex property in the RowCommand event, like this:
Private Sub GridView3_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles GridView3.RowCommand
' Get the row by finding the grandparent of the control (button)
' that initiated the command
Dim theGridViewRow As GridViewRow
theGridViewRow = CType(CType(e.CommandSource, Button).Parent.Parent, GridViewRow)
' Get the index value from the grid view row
Dim index As Integer = theGridViewRow.RowIndex
End Sub
Ok I figured it out myself, I made the default Select button on the grid a Template field. since it was the default button it had the necessary code to make it fire. This was the problem with making a template field from scratch. And by making it a template field it then also gave it a name. So in the RowDataBound code the FindControl method above hides it when a person is not an employee. – R2 Builder 1 min ago edit
I have a following problem. I have a ListView which returns data from SQL table. One of its columns looks like "Ambient/Trance/Goa Trance/House".
All i want to do is parse this column and create buttons for each value, for example a button for "Ambient", a button for "Trance", etc.
I tried to create buttons in ItemDataBound event in the following way:
Dim ListView_Albums_PlaceHolder_Artists As PlaceHolder = e.Item.FindControl("ListView_Albums_PlaceHolder_Artists")
Dim Artists As String() = e.Item.DataItem("album_artists").ToString.Split("/")
Dim ArtistsN As String() = e.Item.DataItem("album_artists_n").ToString.Split("/")
Dim ListView_Albums_Literal_Artists As New Literal
If Artists.Length = 1 Then
ListView_Albums_Literal_Artists.Text = "Artist: "
Else
ListView_Albums_Literal_Artists.Text = "Artists: "
End If
ListView_Albums_PlaceHolder_Artists.Controls.Add(ListView_Albums_Literal_Artists)
For Integer1 As Integer = 0 To Artists.Length - 1
Dim ListView_Albums_LinkButton_Artist As New LinkButton
ListView_Albums_LinkButton_Artist.Text = ArtistsN(Integer1)
ListView_Albums_LinkButton_Artist.CommandName = "Artist"
ListView_Albums_LinkButton_Artist.CommandArgument = Artists(Integer1)
ListView_Albums_LinkButton_Artist.CssClass = "a-03"
ListView_Albums_PlaceHolder_Artists.Controls.Add(ListView_Albums_LinkButton_Artist)
Dim ListView_Albums_Literal As New Literal
ListView_Albums_Literal.Text = ", "
If Not Integer1 = Artists.Length - 1 Then
ListView_Albums_PlaceHolder_Artists.Controls.Add(ListView_Albums_Literal)
End If
Next
They created fine but they didn't work at all. I tried to Add Handler for Click or Command event but it also didn't help.
Please help me to solve my problem!
Edit:
As VinayC suggested I changed ItemDataBound to ItemCreated. That helped, but I faced another problem: as far as I understand e.Item.DataItem or, maybe, e.Item becomes Nothing on PostBacks so the buttons do not work.
How to solve that problem? Thanks once again!
I believe that buttons must be getting created late in page life cycle and hence not responding to events.
You may want to try moving your code in ItemCreated event and use ListView's ItemCommand event to trap these. Yet another suggestion is to assign (different) ID to your link buttons - for example
ListView_Albums_LinkButton_Artist.ID = "A" & Artists(Integer1)
In case, you want to attach an click event handler directly to buttons then ID is must.
So, I solved my problem. The solution wasn't simple but here it is:
In ItemCreated event I firstly count the number of buttons, then save it to ViewState, and only then I create buttons. I had to save the number of buttons to ViewState because on every postback e.Item.DataItem becomes Nothing.
Maybe there is a simplier solution but I found only that one...
Sub OnItemCreated(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs)
Dim ListView_Albums_PlaceHolder_Artists As PlaceHolder = e.Item.FindControl("ListView_Albums_PlaceHolder_Artists")
If Not ListView_Albums_PlaceHolder_Artists Is Nothing Then
If Not e.Item.DataItem Is Nothing Then
ViewState("Length") = e.Item.DataItem("album_artists").ToString.Split("/").Length
End If
If Not ViewState("Length") Is Nothing Then
Dim Length As Integer = ViewState("Length")
For Integer1 As Integer = 0 To Length - 1
Dim ListView_Albums_LinkButton_Artist As New LinkButton
ListView_Albums_LinkButton_Artist.ID = "ListView_Albums_LinkButton_Artist_" & Integer1
ListView_Albums_PlaceHolder_Artists.Controls.Add(ListView_Albums_LinkButton_Artist)
Next
End If
End If
End Sub
Sub OnItemDataBound(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.ListViewItemEventArgs)
Dim ListView_Albums_PlaceHolder_Artists As PlaceHolder = e.Item.FindControl("ListView_Albums_PlaceHolder_Artists")
If Not ListView_Albums_PlaceHolder_Artists Is Nothing Then
If Not e.Item.DataItem Is Nothing Then
Dim Artists As String() = e.Item.DataItem("album_artists").ToString.Split("/")
Dim Artists_N As String() = e.Item.DataItem("album_artists_n").ToString.Split("/")
For Integer1 As Integer = 0 To Artists.Length - 1
Dim ListView_Albums_LinkButton_Artist As LinkButton = e.Item.FindControl("ListView_Albums_LinkButton_Artist_" & Integer1)
ListView_Albums_LinkButton_Artist.CommandArgument = Artists(Integer1)
ListView_Albums_LinkButton_Artist.Text = Artists_N(Integer1)
ListView_Albums_LinkButton_Artist.CssClass = "a-03"
Next
End If
End If
End Sub