I have a small piece of code that iterates through the controls collection on a panel (below) Everything works fine until I want to focus on a control that doesn't support the selectall method i.e. a datetimepicker. Is there any way of determining the type of control and not call the selectall method when the type is datetimepicker. All my other controls support it so that's the only one I need to exclude.
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I am trying to make it so when I use Me.Controls("Timer1") for example I can access specific commands for a timer such as Stop() Start(), I tried CType() and typed in "Timer" as the type but it says the control type can't be converted to the "Timer" type.
View 11 RepliesI can't figure out how to determine the type of an object in a collection. I want to do a For Each ... Next loop over the items in the DropDownItems collection of a ToolStripMenuItem. For those items that are ToolStripMenuItems themselves I want to take some kind of action. (The collection can contain other types of items, such as ToolStripSeparators). So I need to say something like: If Typeof(item) = ToolStripMenuItem Then .
View 1 RepliesI am customizing a DataGridView control. The DataGridView is supposed to be bound to a collection of some type (be it a List(Of T) or ArrayList or whatever), and the idea is that one can easily determine (at design-time in this case) which properties of the type have to be shown in the grid and which column header name they should get. One can do this using an attribute. For example, if I have a class Person with Name, Age and HairColor and I don't want to show the HairColor property, and want to show the Name property as 'Person', I would use:
vb.net
Public Class Person
<Grid.GridOptions(displayName:="Person", visible:=True)> _
Public Property Name As String
[code]....
I do this during run-time by simply looping through the properties of the bound type (in this case Person), retrieving the GridOptions attribute (if any) and checking the values provided. This works just fine except for one thing: I'm not really sure how to determine the type in the databound collection...
At the moment, I cast the DataSource property to an IList and retrieve the type of the first instance in that list (if any). If there isn't a first instance (the list is empty) then I don't know how to get the type... Often I know that it will be impossible to know the type. If someone is binding an ArrayList for example, then it's impossible to know what kind of items he's going to put in that ArrayList. Even the normal DataGridView cannot show any columns when databound to an empty ArrayList. However, the framework's DataGridView does show the columns when bound to, for example, an empty List(Of Person), or a Person array.
I'm pretty sure that casting the DataSource to an IList is not the correct way as all information about the type of items in that list is then lost. But I'm not sure what else to cast it to... ITypedList? IBindingList? I even considered List(Of T) because that's all I am going to be using, but besides the fact that the grid would then obviously only work for a List(Of T) I still don't know how to do this... I don't know 'T' so I can't cast it to a List(Of T)...
Public Shared Function IsType(ctrl As Control, ByVal thisType As ??????) As Boolean Return (TypeOf ctrl Is thisType) I need a function that I can call, for example, to determine if a control is type RichTextbox.dim z as Boolean= IsType(txtBox1, RichTextBox) I ned to determine if a control is a given type (i.e., not always RichTextBox). I don't know what Type to make thisType. Can this be done?Actually I simpified the problem but if the above is answered I can write the function
View 4 RepliesI need to determine the type of a WinForms control in a collection.
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I've created the following basic function to determine whether specific control type is currently loaded:
Private Function IsPreviewerTypeLoaded(Of T)() As Boolean
For Each previewer In LoadedPreviewers
If previewer.GetType().Equals(T) Then
[Code]....
I need to compare each control against the generic type supplied. Equals(T) fails to do the job, producing a compiler error. How to make it correctly?
UPDATE: is the following correct?
previewer.GetType().Equals(GetType(T))
I am trying to dynamically add some css and js elements into an ASP.Net page at runtime, but because this code is used in mutliple controls I need to ensure that the relevant links are only injected once.
Currently I have the folowing code in the OnPreRender event.
Dim head As HtmlControls.HtmlHead = Me.Parent.Page.Header
If Not _useCustomStyles Then
Dim litCustomCss As New LiteralControl("<link rel=" & Chr(34) & "stylesheet" &
[Code]....
Does .Contains look for this instance of an object (which I assume is why this is failing)?
Is there a way to check the controls collection for a specific id? Or am I going to have to write a sub to loop through the existing controls in the collection checking for the id.
I am creating a User Control where I have a property called Items. Items is of type LibraryPanelBarItem Collection (custom class) which contains a collection of LibraryPanelBarItem objects. I would like to be able to add these at design time by using the Collection editor that VS uses for adding things such as treenodes/listviewitems. Ideally I would also be able to declaratively add them to the html syntax. I can get the Items property to show up but I get no intellisense to add the items between the opening and closing tags. [Code]
View 1 RepliesI've make a UserControl and want only buttons can be added to its ControlCollection, if others controls are added, it will throw an exception.
View 4 RepliesI have an ASP.NET app with lots of textboxes all over the page that need updating at various points through program execution. These textboxes actually belong to a certain class, so for easy updating I thought I could create a Dictionary(Of string, object) and add the control.ID and the control to it and then for updating do something like this:
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I have a form with several databound controls. Certain users will be able to change the data in these fields. Is there a way to check whether the data in any databound control has changed? I would like to do this so that I can enable an UPDATE button and flag a warning to the user that they must save their changes.
View 9 RepliesI want to scan a directory and see what files are NOT bmp image files. As the file extension can lie I need to interrogate the file itself. I found some code here [url]...?ID=112 that does exactly this however it was written for VB5 and is 13 years out of date! I tried compiling it however VB 2010 baulked and I don't have the expertise to make it work.
View 1 RepliesHow can I programatically determine if a file with a certain extension (XLS, for example) is really an Excel file and not a VBS file, for example, that has the XLS extension?
View 1 RepliesI'm a bit confused here. I'm copying all the controls from one form to a panel on the main form and for some reason only about half of them copy.
Private Sub switchComponent()
Dim selection As String = TreeView1.SelectedNode.Text
Panel1.Controls.Clear()[code]....
When stepping through the code, serverDic(selection).Controls has 12 elements, but only 6 of them get copied. Next time this gets called, only 3 get copied. Does Panel1.Controls.clear() somehow kill the references?
EDIT: Just to show that there are infact 12 elements in the collection:
Im trying to loop through a collection of controls see code:
Private Sub addZeros()
For Each ctrl As Control In Me.Controls
If TypeOf ctrl Is GroupBox Then
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I often see code snippets for handling each control of a certain type on a form or panel, etc.They always start with For Each ctrl and the do a test for control type.Many .NET users are not aware, as I was not until I tried it recently, that we can LINQ on the controls collection.Below is a simple sub I created for resetting every checkbox on a panel I use as a validator.
Private Sub ResetCheckBoxes(ByRef pnl As Panel)
Dim ctrls as System.Collections.Generic.IEnumerable(Of Object)
ctrls = From c In pnl.Controls Where TypeOf (c) Is CheckBox
[code]....
how do you determine cell type of a column?
View 7 RepliesI need to check a value within the registry. The application (Cisco VPN) is a 32bit app so uses Wow6432Node when installed on 64bit operating systems.What would be the best method of selecting which string to use? Checking the OS for x64, attempting to read one and then the other if the first fails? Or is there a better method?
Dim keyName64 As String = "HKEY_LOCAL_MACHINESoftwareWow6432NodeCisco SystemsVPN Client"
Dim keyName32 As String = "HKEY_LOCAL_MACHINESoftwareCisco SystemsVPN Client"
Using .net 4.0 framework?:
Dim registryKey As RegistryKey
If Environment.Is64BitOperatingSystem = True Then
registryKey = registryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry64)
Else
registryKey = RegistryKey.OpenBaseKey(Microsoft.Win32.RegistryHive.LocalMachine, RegistryView.Registry32)
End If
I am converting a VB.Net application to C#. Everything else is going great. Except this bit. I have a function which builds menus,sub menus and seperators from a database. It can build a MenuStrip or a ContextMenuStrip which can then be assigned to a form.
This means that menus can be extensive and conpmex but managed outside the application, which I also use as part of my security access model. All menus are controlled from the database externally, it also means I can develop visual tools (Treeviews etc) to manage user menus. The application uses menus extensively which is by design.
Programmatically I want to assign an eventhandler to every item that isnt a dropdown or a seperator
In VB I would do this, (works perfectly)
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"System.Windows.Forms.ToolStripItem' does not contain a definition for 'DropDownItems' and no extension method 'DropDownItems' accepting a first argument of type 'System.Windows.Forms.ToolStripItem' could be found (are you missing a using directive or an assembly reference?)"
I am still developing this function, but here is what I am intending it to do. This function will accept an Object, then try to determine its type. There are a specific set of types I am looking for: Integer, Boolean, Date, String. What I have so far is pretty privative, but it seems to be working so far:
Private Function DataType(ByVal entry As Object) As ValueType
Try
If IsNumeric(entry) Then
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I have a class C(Of T). I want to determine if some given value has type C, regardless of what T is. For example, I might want to determine if a value is a strongly-typed list, regardless what type of items the list stores. I just need to know how to do it in VB.net. In Java the syntax is like this:
var result = obj instance of Gen2<?>;
Does anyone know how I can access the FontDialog's controls collection? I would like to disable the Font Style ListBox, set the Font Style's TextBox to readonly and disable the UnderLine and StrikeOut CheckBoxes.
View 3 RepliesMaybe if I knew the right termanology, I could find the answer myself.. I am going to run a fairly long list of "If"s that will determine if certain controls appear on the form or not. In it's simplest form would be:
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How to get the last instance of label control in List (of Control) using linq?
View 4 RepliesI am writing a simple control translation function that reads an XML file containing control names and their localized text. Within the application, each time a form is loaded, it iterates through every control and tests to see if that control is defined in the XML file. If it is, it then sets the control text to whatever localized text is defined in the XML file.
There are some tests and additional requirements (i.e. nested loops) for TabControl and MenuStrip etc., but the control that is giving me the most trouble is the ContextMenuStrip.[code]...
I have the following VB.NET function, for example:
Public Function MyFunction (Of TData) (ByVal InParam As Integer) As TData
End Sub
How do I, in a function, determine if TData is a NULLable Type?
I have a dataset and want to know the data type of a specific column. The GetType returns datacolumn not string or integer etc.iggy!
View 2 RepliesI'm interested in having a generic 'Try Catch' clause, with some case statements or if/than statements within the Catch part so that I can handle different error types differently. some way to get ex.Errorcode or ex.ErrorType that differentiates the different errors to a unique value.
How can this be done?
Try
'some code taht will throw an error'
Catch ex AS Exception
If ex.ErrorCode = 20 then
' Do something'
[Code].....
I have the following VB.NET function, for example:Public Function MyFunction (Of TData) (ByVal InParam As Integer) As TDataEnd Sub
View 5 Replies