I want to create an application that is able to change the selected value of the dropdownlist in the web page.
I tried to use the code below to change the selected value of the dropdownlist:
Dim TypeSelection As HtmlElement = WebBrowser1.Document.GetElementById("dropdownlist1")
Dim TypeSelectionOption As HtmlElement = TypeSelection.GetElementsByTagName("option").Cast(Of HtmlElement).First(Function(el) el.GetAttribute("value") = "ABC")
TypeSelectionOption.SetAttribute("selected", "true")
TypeSelection.InvokeMember("onchange")
The selected value of the dropdownlist had been changed, but it can't post back to the server, it just hangs at there. I tried to create a testing page to test my code, the code is working & able to post back to the server.
Is there any other method to change the selected value of the dropdownlist, that is able to post back to the server?
Related
currently I am working on a project named online exam.
All the controls are dynamically created.
I have a webpage where I want to display the student details.
I displayed those details correctly in a table.
Now here comes the time to edit those details.
To edit a record I use the linked button named edit.
When a user clicks on that Linked button the data in that row is replaced with new textboxes.
Upto here I am OK.
Now when I click on the save changes button after making changes to the textboxes.
The old values are not replaced by the new values and the old values remains.
The code for creating textboxes in the table is as follows :
Public Sub Edit_Click(ByVal sender As Object, ByVal e As System.EventArgs)
For x As Integer = 0 To EditList.Count - 1
If sender.id.substring(4) = EditList(x).ID.Substring(4) Then
Session("PreviousRollNo") = RollNoList(x).Text
Dim txtName As New TextBox
txtName.Text = NameList(x).Text
NameList(x).Text = ""
NameList(x).Parent.Controls.Add(txtName)
txtList.Add(txtName)
Dim txtCourse As New TextBox
txtCourse.Text = CourseList(x).Text
CourseList(x).Text = ""
CourseList(x).Parent.Controls.Add(txtCourse)
txtList.Add(txtCourse)
Dim txtAdmissionDate As New TextBox
txtAdmissionDate.Text = AdmissionList(x).Text
AdmissionList(x).Text = ""
AdmissionList(x).Parent.Controls.Add(txtAdmissionDate)
txtList.Add(txtAdmissionDate)
Dim btnSaveChanges As New Button
btnSaveChanges.Text = "Save Changes"
EditList(x).Text = ""
EditList(x).Parent.Controls.Add(btnSaveChanges)
AddHandler btnSaveChanges.Click, AddressOf btnSaveChanges_Click
Session("EditButtonClicked") = True
Dim btnCancel As New Button
btnCancel.Text = "Cancel"
DeleteList(x).Text = ""
DeleteList(x).Parent.Controls.Add(btnCancel)
AddHandler btnCancel.Click, AddressOf btnCancel_Click
Session("CancelButtonClicked") = True
txtName.Focus()
Exit For
End If
Next
End Sub
The code for Save Changes button is as follows :
Public Sub btnSaveChanges_Click(ByVal sender As Object, ByVal e As System.EventArgs)
If txtList(0).Text = "" Then
Dim trError As TableRow = New TableRow
Dim tdError As TableCell = New TableCell
tdError.ColumnSpan = 7
Dim lblError As New Label
lblError.Text = "Please enter name of the student."
lblError.ForeColor = Drawing.Color.Red
tdError.Controls.Add(lblError)
trError.Controls.Add(tdError)
tbl.Controls.Add(trError)
ElseIf txtList(1).Text = "" Then
Dim trError As TableRow = New TableRow
Dim tdError As TableCell = New TableCell
tdError.ColumnSpan = 7
Dim lblError As New Label
lblError.Text = "Please enter the course."
lblError.ForeColor = Drawing.Color.Red
tdError.Controls.Add(lblError)
trError.Controls.Add(tdError)
tbl.Controls.Add(trError)
ElseIf txtList(2).Text = "" Then
Dim trError As TableRow = New TableRow
Dim tdError As TableCell = New TableCell
tdError.ColumnSpan = 7
Dim lblError As New Label
lblError.Text = "Please enter the Admission Date"
lblError.ForeColor = Drawing.Color.Red
tdError.Controls.Add(lblError)
trError.Controls.Add(tdError)
tbl.Controls.Add(trError)
Else
Dim cb As New OleDbCommandBuilder(da)
Dim editRow() As DataRow
editRow = ds.Tables("Student_Detail").Select("Roll_No = '" & Session("PreviousRollNo") & "'")
editRow(0)("Name") = txtList(0).Text
editRow(0)("Course") = txtList(1).Text
editRow(0)("Admission_Date") = txtList(2).Text
da.Update(ds, "Student_Detail")
Page.Response.Redirect("ChangeUserDetails.aspx")
End If
End Sub
I get the error sying that array is out of the bounds. on the first line of the btnSaveChanges_Click.
It means txtlist is always cleared when I click on Save Changes Button.
So I stored txtList in a Session like Session("txtList") = txtList.
and retrieved the data from that. But now I get the old values of the textbox instead of the newer ones.
Here txtList is a list (of Textbox)
Firstly, welcome to the ASP.NET WebForms Page Life Cycle. Remember its pattern with the simple mnemonic: SILVER = Start, Init, Load, Validate, Events, Render.
Secondly, HTTP is stateless. WebForms does an amazing job of hiding this fact from you using ViewState until you do something a little out of the ordinary (as you're now attempting), and it all appears to fall apart. What's really happening is that you're starting to see side-effects of how WebForms is managed, and how it's not as much like WinForms (or another stateful system) as you might think.
When you're responding to an event server-side in WebForms, it's easy to get the impression that nothing has changed. That the entire page is as you left it "last time". All the controls are there, the values you may have set programatically are still set. Magic. Not magic. What's actually happened is the entire page has been re-constructed to respond to that event. How was it re-constructed? By a combination of your page definition (markup), actions taken in control event handlers, and the form data posted back by the client.
Confusing? OK, let's consider an example. Say you've got a page with two controls on it. A textbox named txtInput and a button named btnSubmit with event handler btnSubmit_Click. When the user first requests the page, the HTML for these controls is derived from your markup (aspx page) and returned to the client. Next, the user sets a value in txtInput and clicks the submit button. The server then re-creates the page from scratch based on your markup. At this early stage of the life-cycle, the controls still have their default values. We then hit the Load stage of the life-cycle, and "if the current request is a postback, control properties are loaded with information recovered from view state and control state." In other words, by the time the life-cycle gets to Init, the control has been created from markup, but still has its default value. The Load stage then sets the value according to Postback data.
Left wondering how this applies to your scenario? You're adding your dynamic controls in response to a control event. There's two things wrong with that:
It's too late in the page life-cycle for Init to set the values based on data posted back from the client (recall SILVER, Event is after Init).
Your button click event handler is only run once, in response to the postback where the user clicked the button. But remember on each postback the page is entirely re-created. So the dynamic controls no longer exist as far as the server is concerned! You'll notice that not only are the controls not present server side when responding to the submit event, but after the page has handled it, they're no longer present client-side either.
So what's the answer? Well the "Life-Cycle Events" section of the page I linked offers a clue. It states that the PreInit event be used to (among other things) "Create or re-create dynamic controls". Why would we do it in PreInit? So it's early enough in the page life-cycle for the later events to properly handle it (like setting the values posted back from the client).
Now, I know, you want to add the controls based on the user clicking on the button. How does that fit? The trick is that you've got to manage the "state" yourself. Huh? the state? By this I mean MyDynamicControlsShouldBeShown = true / false. When the button is clicked, creating the controls in response to the button-click event handler is the right action (there's not really any choice there). But you need to store that state somehow so you know on subsequent requests to the page, whether those controls should be re-created in PreInit. One neat option would be to check for the ID of your dynamic control in Request.Form.Keys. If the control ID is present in the Keys collection, then the user is posting back a value for the control, so you should re-create it.
A side-note on the use of Session
Hopefully based on the above you've realised why putting the controls into Session didn't work. But to be clear, the controls you put into the Session object were no longer part of a page that existed (remember, the page gets completely re-created for each request. Those controls were no longer hooked up to the Page events, so didn't get their values populated between Page Init and Load. If somehow it did work, it still wouldn't be a particularly good idea, as Session is not per-request. So what would happen if a user had the same page open in multiple tabs? Strange things, that's what.
hello again.
We have a webform that employees use to make request for such things as VPN access to the company resources from remote locations.
I am populating a dropdownlist box from Active Directory. This works fine.
Then I have a textbox that is also populated from Active Directory by simply assigning the value of the logged in user as shown:
textbox1.Text = User.Identity.Name
Based on the value of my name assigned to textbox1.Text
The rest of the texboxes are populated with my work information with the following code:
textbox1.Text = User.Identity.Name
textbox1.Text = StrConv(textbox1.Text, vbProperCase)
txtdate.Text = DateTime.Now.ToString("MM/dd/yyyy")
Try
'Creates a Directory Entry Instance with the Username and Password provided
Dim deSystem As New DirectoryEntry("LDAP://OU=Departments,DC=domaname, DC=com", "usrname", "password")
'Authenticacion type Secure
deSystem.AuthenticationType = AuthenticationTypes.Secure
'Creates a Directory Searcher Instance
Dim dsSystem As New DirectorySearcher(deSystem)
'sAMAccountName is equal to our username passed in.
dsSystem.Filter = "sAMAccountName=" & textbox1.Text
'Properties that the Procedures will load from Active Directory
dsSystem.PropertiesToLoad.Add("mail") 'email address
dsSystem.PropertiesToLoad.Add("department") 'dept
dsSystem.PropertiesToLoad.Add("physicalDeliveryOfficeName") 'office
dsSystem.PropertiesToLoad.Add("title") 'title, eg programmer1
dsSystem.PropertiesToLoad.Add("telephoneNumber") 'phone
dsSystem.PropertiesToLoad.Add("streetAddress") 'street address
dsSystem.PropertiesToLoad.Add("l") 'city
dsSystem.PropertiesToLoad.Add("st") 'state
dsSystem.PropertiesToLoad.Add("postalCode") 'zip code
dsSystem.PropertiesToLoad.Add("EmployeeId") 'empid
dsSystem.PropertiesToLoad.Add("givenName") '//first name from active directory
dsSystem.PropertiesToLoad.Add("sn") '//lastname from active directory
'Find the user data
Dim srSystem As SearchResult = dsSystem.FindOne()
'Obtains the properties recently loaded
txtemail.Text = srSystem.Properties("mail").Item(0).ToString
dept.Text = srSystem.Properties("department").Item(0).ToString
office.Text = srSystem.Properties("physicalDeliveryOfficeName").Item(0).ToString
txttitle.Text = srSystem.Properties("title").Item(0).ToString
phone.Text = srSystem.Properties("telephoneNumber").Item(0).ToString
workaddress.Text = srSystem.Properties("streetAddress").Item(0).ToString
city.Text = srSystem.Properties("l").Item(0).ToString
state.Text = srSystem.Properties("st").Item(0).ToString
zipcode.Text = srSystem.Properties("postalCode").Item(0).ToString
hiddenempId.Value = srSystem.Properties("EmployeeId").Item(0).ToString
HiddenFName.Value = srSystem.Properties("givenName").Item(0).ToString
HiddenLName.Value = srSystem.Properties("sn").Item(0).ToString
This works fine as well.
Here is where my problem lies.
Initially, when the user logs in, based on logged user name from Active Directory, the rest of the textboxes get populated with the user's info.Sorry for repeating myself here.
However, sometimes, the user logged in is not necessarily the user needing reguest.
In other words, I can log in to fill a request for another employee.
In this case, I am required to select the name of the user I am completing the request for from the dropdownlist that is populated from Active Directory.
When I select this name from dropdownlist, it replaces my own name on textbox1.Text.
This works fine but the rest of the textboxes retain my own information.
What do I need to do to ensure that the name that replaces my original name on textbox1.Text also replaces the information on the rest of the textboxes?
I will post additional information as requested.
Many thanks in advance
Instead of loading all the text boxes when the form loads, load them from the TextChanged event of the user name text box. That way, any time the user name text box changes, all the other text boxes will automatically be re-loaded to reflect the change.
I'm trying to allow my users to enter in large lists of data using an ASP.Net GridView control. The affect I'm trying to create is to make the GridView control act like a spreadsheet. The user can freely enter data and tab from column to column and row to row. The user can use a button at the bottom of the page to add rows as needed. There is also a button at the bottom of the form to save as needed.
To do this, I created a DataTable with a bunch of empty rows and bound it to a GridView. The GridView's columns are template columns that contain textboxes. So, when the page opens, it actually looks like a spread sheet. When the user hits the add rows button, I just add another ten rows to the DataTable the GridView is bound to and it works like a charm.
The issue I'm running into is reading the data that the user entered. When the user hits the paging link or the update button, I would like to update the DataTable with the data the user typed in. Here is what I have.
Private Sub UpdateDataTable()
Dim objCatRow As clsCategoriesRow = Session("gvCategoriesRow")
Dim drQuery() As DataRow = Nothing
Dim drRow As DataRow = Nothing
Dim objRow As GridViewRow = Nothing
Dim intRecNo As Integer = 0
Dim txt As TextBox = Nothing
Dim lbl As Label = Nothing
'Loop through all of the rows in the grid view control
For Each objRow In Me.gvCategories.Rows
'Get the label that contains the identity column
lbl = objRow.Cells(GridColumns.Category).FindControl("lblItemRecNo")
intRecNo = lbl.Text
'Update the datarow bound to this grid view row
'First, query the datarow from the data table
drQuery = objCatRow.Table.Select("recno = " & intRecNo)
'Make sure our query returned a row
If Not IsNothing(drQuery) AndAlso drQuery.Count > 0 Then
'Get the value from the textbox in the grid view
txt = objRow.Cells(GridColumns.Category).FindControl("txtItemCategory")
'Upadte the data row with the value the user entered
'THE VALUE IN txt.Text IS EMPTY. HOW CAN I GET THE VALUE THE USER TYPED IN?
drQuery(0)("Category") = txt.Text
'Get the value from the textbox in the grid view
txt = objRow.Cells(GridColumns.SortORder).FindControl("txtItemSortOrder")
'Upadte the data row with the value the user entered
drQuery(0)("sortorder") = txt.Text
End If
Next
End Sub
The issue is that this is not returning what the user typed in. The line
txt = objRow.Cells(GridColumns.Category).FindControl("txtItemCategory")
returns a reference to the textbox in the templated column. But, it contains the previous value, the value from the view state, not the value the user typed in.
How can I get the value the user typed into the grid?
I want to mention that I know how to add EDIT and UPDATE buttons to each row. I would like to avoid doing that way if I can. My users have huge lists of data to enter in and that approach would make the application unusable.
Thanks in advance,
Mike
The form data posted by the user is found in the Page.Request.Form.Item collection. The Page.Request.Form.AllKeys lists the "keys" associated with all of the form item values.
If Page.Request.Form.HasKeys Then
For Each key as String In Page.Request.Form.AllKeys
' step through the keys and use Page.Request.Form.Item(key) to get the data entered
Next
end If
After testing, I was able to get the data from the Request.Form data or the GridView control during page.load on postback, as long as you don't bind the control on postback, but only during the initial request ("GET").
Keep in mind, controls have to be re-created for each request to the page. The Request data posted is used by ASP.NET to repopulate form data controls only after the controls are re-created on the page and the ViewState for the controls is processed, etc.
Request.Form collection
ASP.NET Page Life Cycle
You should replace this:
txt = objRow.Cells(GridColumns.Category).FindControl("txtItemCategory")
with this
txt = objRow.Cells(GridColumns.Category).FindControl("txtItemCategory").Value
There are test.aspx page and test.ascx web user control.
I have a button in test.aspx = btn_test and above code in my button is :
Dim ct As Control = Page.LoadControl("test.ascx")
Panel1.Controls.Add(ct)
There is a dropdownlist with value 1 to 10 in test.aspx and there is label_test in test.ascx
I need some code when test.ascx loading, get dropdownlist.selectedvalue and show it in label_test.
Please help me !
There are a number of ways to implement this. One you could try would be to cast the test.ascx web control being loaded like so (replace TestControl with the class name for the control):
Dim ct As TestControl = CType(Page.LoadControl("test.ascx"), TestControl)
And then create a public property in the control which you would use to set the value from the DropDownList.
Dim ct As TestControl = CType(Page.LoadControl("test.ascx"), TestControl)
ct.DropDownListValue = DropDownList.SelectedItem.Value
Panel1.Controls.Add(ct)
This property would then be used to set the labels value (either directly using the set accessor or via a method within the test.ascx control).
How to set crystal report's textbox value at run time. I have a textbox in section2 (page header) in crystal report, now I have to set Text property of this textbox at run time. Basically I have to pass user name in this textbox.
You can change textbox text in runtime. You can use this:
using CrystalDecisions.CrystalReports.Engine;
rptMyReport report = new rptMyReport();
TextObject to = (TextObject)report.ReportDefinition.Sections["Section2"].ReportObjects["textboxname"];
to.Text = newvalue;
The another way is to use parameters.
If you have the user name before the report opens you can add a parameter field (string) to the report and then put that field on the report where you want it to appear at runtime. You will just need to pass it into the report as a parameter just like you would any other parameter.
Dim UserName As String = "BukHix"
crDOC.SetParameterValue("UserName", UserName)
try this
((TextObject)rpt.Section2.ReportObjects["Textbox"]).Text = "yourvalue";