Setting Type Dynamically At Run Time In Of Clause In .Net?
Oct 10, 2011
I'm using LINQ to Entities to generate typed result sets in VB.Net. I've got a generic Report class as follows:
Public Class Report
Public Property Name As String
Public Property SQL As String
Public Property Type As String
End Class
Then in the calling scope I want to have code that does something like:
' create my data context
Dim context As New MyAppEntities
' get a report object out of a dropdown list
[Code]....
So far I'm finding that .Net won't let me set the type in the (Of Type) clause on the fly at runtime.
Does anyone know how to do this?
I've tried changing the Type property of the Report class to an object of type Type, but that doesn't work either.
BTW, I know there are alternative ways to accomplish the same thing, but I'm working with external constraints that make this what I've got to work with right now.
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Nov 22, 2011
I have two DataTables, PersonInformationDataTable on which i only know about a "CityName" field, and another CityInformationDataTable, which has a few constant fields and i do a query like
ResultOfQuery = From person As DataRow in PersonInformationDataTable
From CityInfo As DataRow in CityInformationDataTable
Where (person("CityName) = CityInfo("CityName"))
Select ?? all person info ?? , Country = CityInfo("Country"), Tongue = CityInfo("SpokenTongue")
I would like again all the person fields with their values in the enumerable result.
the result would be like : name=. I don't know how many fields or the fields name of PersonInformationDataTable in advance. With a SQL Query, i could write a string with a loop on CityInformationDataTable columns and have a custom select string like : "Select Name,
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Aug 18, 2010
I am using VB 2008 and Access Database.
Also using Typed DataSet.
My Question is how do i add Where Clause to TableAdapter at Run Time
I want to allow User to select Fields tobe filtered and values they should have.
For this my Select query is common but no. of records it will show will depend on User selected criteria.
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Aug 10, 2010
Consider the requirement to always declare Option Strict On. We'll always need to declare variables with the As keyword. What would be the type of an anonymous type?Example : Dim product As ... = New With { Key .Name = "paperclips", .Price = 1.29 }
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Feb 23, 2010
I've just opened a project I was working on yesterday perfectly well only to find it's gone nuts. I'm getting this error ..."Handles clause requires a WithEvents variable defined in the containing type or one of its base types."... on each one of my Sub declarations!
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Feb 19, 2012
Columns 0 & 1 are filled from a DataAdapter from Access Database and three are added. I had this working, but I changed it to check for the column "Feed" so I could add several Locations. At first this worked,but I did someething in perfecting it and it now fails after filling the first row of the datagridview (dgvFdMed).I ran a check and the table LotsTab has 8 rows filled. Column 1 & 2 are strings and the database appears they are fine. The added columns have just been created with no value. My plan is to enter the values and then use the data from the grid.
Private Sub sfillGrid(ByVal Loc As String)
Dim i As Integer
Dim column As DataGridViewColumn
[code]....
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Oct 6, 2011
I get the error
Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
in the following code..
Public Sub selCurrentManuf_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles selCurrentManuf.SelectedIndexChanged
End Sub
The drop list to go with it is the following...
<asp:DropDownList
OnSelectedIndexChanged="selCurrentManuf_SelectedIndexChanged"
selectedvalue='<%#Container.DataItem("c1_manufidcurrent")%>'
[code]....
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Aug 23, 2009
I created a lable to handle DateTime = Now, It works fine. but when I moved it inside a FormView I Get the following Message. Handles clause requires a WithEvents variable defined in the containing type or one of its base types?
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Oct 19, 2010
Public Class Form1
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Click, Open.Click,Name.Click
SelectVid.ShowDialog()
End Sub
[code]....
I keep getting this error:
Error1'.' expected.
Error2Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
Error 2 is also error 3
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Dec 8, 2011
I am auto generating data grid and I am using check box in Data grid View,Now i am invoking check box state changed event but it produces the following error Handles clause requires a With Events variable defined in the containing type or one of its base types.
Here the code
Private Sub PRNT_CheckedChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles PRNT.CheckedChanged
Some Stuff.
End Sub
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Mar 25, 2010
I am in the processing of moving an app from VB to C# but some of the classes I will just be moving to VB dlls to access from the main C# app. In doing this I am trying to get the VB dlls to utilize the main C# class lib. In this C# lib I have an abstract clase called base process, it sets up a background worker and handles all the progress tracking, errors, and even reports an ETA. To use this in a derived class in C# you would just do this...
public class SomeLongProcess : Common.Multithreading.BaseProcess
{
public void start()
[code]....
The problem is that if I do the equivelant in VB I get an error "Handles clause requires a WithEvents variable defined in the containing type of one of its base types". Well I can't do a WithEvents in the base class because it is C# so..
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Aug 26, 2011
I am trying to follow this thread
[URL]
and I have it pretty close but have one error.
Quote:Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
That error is on both of these, in blue
Private Sub SpellChecker1_DeletedWord(ByVal sender As Object, ByVal e As NetSpell.SpellChecker.SpellingEventArgs) Handles SpellChecker1.DeletedWord
'save existing selecting
[code]....
I have added the reference, I have also added them to the toolbox. My dictionary is all set. What did I miss?
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Nov 22, 2011
i am getting errors on last two event handlers. what did i do wrong?
Error - Handles clause requires a WithEvents variable defined in the containing type or one of its base types.D:Shipping ApplicationShipping ApplicationForm1.vb75136Shipping Application
Error - 'PrintDocument1' is not declared. It may be inaccessible due to its protection level.D:Shipping ApplicationShipping ApplicationForm1.vb1119Shipping Application
[code]....
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May 11, 2009
Just upgraded a VS 2005 ASP.NET 2.0 website to VS 2008 ASP.NET 3.5. There was an error on the Sub Button_Click. It seemed to be a minor error, the website and the button worked just fine, as usual. What does the error mean?
Protected Sub btnDEreports_Click(ByVal
sender As
[code]...
Error 20 Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
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May 29, 2011
What is the point of the max value of a scrollbar when it can't be attained? I put a horizontal scroll bar on a form and set the maximum value dynamically. After a bit of testing, there is no way for the scroll bar to attain this maximum value. Instead, I am always ending at Max-2. It always comes up two short. So what is the point of the maximum value if it can't be attained?
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Aug 9, 2011
My coding, I got error: Error Handles clause requires a WithEvents variable defined in the containing type or one of its base types.
For information i am using visual studio 2005. Here i highlight my probleam with in my coding
Public Class Admin
Private Sub TextBox6_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs)
End Sub
[CODE]...
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Feb 21, 2012
I declare my dates as the following in my code:
Dim DeliveryDate as Date
But i am now trying to declare time however i keep getting an error because i cannot get the type correct. I tried the following but get the following error: "Conversion from type 'Timespan' to type 'integer' is not valid".
Dim DeliveryTime as DateTime
Dim DeliveryTime as Integer
In my database the DeliveryTime type is set to Time(7) so i would assume there should be 'Time' which i could use to declare it, but there isnt. What is the correct type i should be using?
Here is my exact code. There error is Input string was not in correct format:
GraphDate4 = String.Empty
DeliveryProducts = "{ name: 'DeliveryProducts', data: ["
If DataReader4.HasRows Then
[Code].....
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Dec 14, 2011
I have a generic Class I'm using to hold information loaded from a database.I have a method which takes a DataRow as an argument, uses the object's known column name and extracts the data from the DataRow, such that:Dim loadData As T = CType(myDataRow("myColumnName"), T))works as my default assignment in most cases.Unfortunately, due to some horrifying design constraints, some of my columns may be null, and may also be taken from enumerations.This means that when <T> is Nullable(Of SomeEnumeration) the above code does not work because I can't cast 0 directly to SomeEnumeration.Zero.Is there some way to check whether <T> is Nullable(Of [Enum])? Or some way to write a method which allows Integers to be cast to Nullable(Of [Enum])?I feel like I'm forgetting something that would allow me to write one of the other of these, but my weak google-fu is turning up nothing.
EDIT: Okay, thanks to dasblinkenlight's answer below, I can detect when this circumstance is occurring, but what I need to do now is to take a type <T> which I know is Nullable(Of SomeClass), get a type reference to SomeClass and then create a new object of type Nullable(Of SomeClass) and assign that to LoadData.My problem was that I had a lot of difficulty in finding any function which would accept baseType as an actual Type.Parse accepted baseType as a parameter, I knew baseType was an [Enum] type because of dasblinkenlight's code, so I was, in this instance, able to code a solution. It's a solution which is very specific to my problem (i.e., T is Nullable(of SomeEnumeration)), but it's a solution nonetheless.
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May 16, 2012
when i am selecting form the xaml file a button and then tap event from the right (in order to set the tap event) it auto generates this sub :
[Code]....
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Jun 11, 2011
I have a webbrowser.So once webbrowser is completed then it should add the specified value in [TEX] [/TEX] value in php.When webbrowser is completed then this http://screensnapr.com/e/LCgzhP.png value will be our specified value.I tried using this on webbrowser completion. Webbrowser1.Document. getelementbyid("the_file").SetAttribute("value", "C:/test.jpg")
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May 15, 2010
Is it possible to declare a variable and to choose it's appropriate type during runtime?
it should be something like this (of course, the last line does not work):
'Determine what type of variable is needed later
Dim myVariableType As System.Type = System.Type.GetType("System.String", True, True)
'Create variable with needed type
Dim myVariable As myVariableType ' Should be a string variable in this case
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Nov 28, 2011
I want to have a bunch of different screens, yet I don't want to have to use 20 different forms (I'm pretty sure that's bad practice anyways), and I don't want to lay down all the controls at once in the designer because then things get messy. I had an idea of running a sub on startup that would dynamically generate all the controls I need with all the right coordinates and settings, and then dump al the ones needed for a specific screen into a Panel. Then I return an ArrayList of panels, and pull out the correct panel to attach to the form when I need that screen. The only problem is that my form will not have any implicit knowledge of its controls, so I'm assuming I wouldn't be able to use the WithEvents / Handles. keywords to declare handlers in the form class (which is what I'd rather do).
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Nov 8, 2010
What I am trying to do is allow for my objects to know when their data has changed on the database (so they are able to raise an event to let the user of the object know about the change).After following several tutorials on how to get SqlDependency working, I have finally managed to get it to let me know when something changes (although it also appears to let me know when I make the initial connection to it too, but that isn't a problem as I can work around that).The function that I have which sets up the SqlDependency is;
Public Function getMembers() As List(Of User)
Dim conn As New SqlConnection(_connectionString)
Dim sql As String = "SELECT UserGroupUserID, UserID, GroupID FROM dbo.xtblUserGroupUsers
[code].....
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Mar 24, 2010
I have three settings Pleas,DocketSheets,AllTrays (strings). How to I set the value and save them for ever?
I've tried.
My.Settings.AllTrays = "Tray1;Tray2;Tray3;Tray4"
My.Settings.Save()
but it says that AllTrays is readOnly. Are the settings only retrievable and not settable or updatable?
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Dec 8, 2009
I am dynamically declaring types (using ModuleBuilder.DefineType() which are used to allow for strongly typed data sets from a CSV file. However when the user adds or alters a column definition I'd like to remove and rebuild the data type. How I drop and recreate a type - do I have to unload the whole assembly or how is it done?
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May 27, 2009
Why does this give variable A the value of zero (instead of setting it to nothing)?Dim A as double? A=If(2<3, Nothing, 6)
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Jun 14, 2009
How you set data type to string? I am using this source:
Dim Resp As String = AxInet1.OpenURL("[URL]", vbNullString)
TextBox1.Text = Resp
I need to replace the vbnullstring. On other forums, people are saying to use icstring but still i am getting an error that it is not declared and I added reference to imports system.text.
Errors:
A first chance exception of type 'System.Runtime.InteropServices.COMException' occurred in AxInterop.InetCtlsObjects.dll
A first chance exception of type 'System.ArgumentException' occurred in AxInterop.InetCtlsObjects.dll
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Feb 3, 2011
Basically, my app has the main form and a windows form "splash". Let me explain, this "Splash" is a WINDOWS FORM, not a splash form; its just named splash because I want to use it for that reason.In my project settings, my main form is my startup, and the splash form is my splash. This splash form has been coded on a timer for 10 seconds, but when I set the splash form as the splash setting, the form shows up for 1 second and goes to the main form.What I need is to edit the splash setting time from 1 second to x# seconds (preferebly 10)
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May 18, 2012
I am using Visual Basic 2010 for a project.My project requires to place a TRANSPARENT button on top of an image (placed inside a picturebox). for that to work, i need to set the button's parent to the picturebox. Is there a way to do that in design time? I cannot find anything on the property tab. The reason i want to set it on design time is because my project will have a motherload of buttons and it will a pain to code the parent change....
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Sep 25, 2011
In VB6 I would simply retrieve the user font setting from the .ini file, load into variables and then apply to the appropriate control.
text1.fontbold = userfontbold
text1.fontitalic = userfontitalic
text1.fontunderline = userfontunderline
etc.
I'm struggling to understand how to do this vb.net The following code works, but sets all three at one time
Text1.Font = New Font("Courier", 10, FontStyle.Bold Or FontStyle.Italic Or FontStyle.Underline)Since the user can have many different combinations of settings, I would like to be able to add just one of these properties at a time, but can't seem to figure out how to do it.
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