Syntax Choice For Type Parameter Variance In C# And VB
Apr 12, 2010
In both C# and VB, type parameter modifiers are used to express the variance of type parameters. For example, the C# version looks like:
[Code]....
Since variance specifications basically restrict where and how a type parameter can be used, I tend to think of them as additional constraints on type parameters. I'm just curious as to why they aren't represented so. I mean, why are they represented in both languages as additional modifiers on type parameters, instead of being added to the type constraint list? If they were type constraints, the C# version would've looked like:
I want to have a "template" function that can receive different parameter and a type parameter, like:[code]But Vb told me that tupeList is not defined... is there a way I can do that?
I have four drop down lists here and I've assigned the datasource and displaymemberproperties so they are populated by a table. When I run the program and select a choice, all four of them get updated with the new choice.
i am getting all filenames from a directory.parsing out the directory names & the .vb extension then converting those filesnames to classes.Every file in the LPCriteria direcotry is its own class with a "Evaluate" function.[code]
how i'd solve for variance and Std. deviation. the project is meant to record housing prices, put them in a list box, and then compute these calculations
Public Class Form1 Dim intclicks As Integer = 0 Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load End Sub
I need to create a function which have either 1 parameter with a string as data type or 2 parameters with double as data type.Something like the substring method.
How can I calculate standard deviation and variance of a field in my database by using OleDb and SQL language in vb 2010. I used VARIANCE and STDDVE and VAR_SAMP but they are undefined. There is other function for do this or there is any way to define this kind of SQL functions to OleDb?
I am trying to convert the following code for the variance calculation public static double Variance(this IEnumerable<double> source){ double avg = source.Average(); double d = source.Aggregate(0.0, (total, next) => total += Math.Pow(next - avg, 2)); return d / (source.Count() - 1); } Described on CodeProject into corresponded VB.NET lambda expression syntax, but I am stuck in the conversion of Aggregate function. How can I implement that code in VB.NET?
What is the suitable type for these 3 syntax in vb.net? i can't find in this page url..I've tried to convert the first one to -->byval ID() as byte is not working
I want a box(listbox or textbox) in VB.Net form. then when I running the program, user can type a value in the box. can I ask user to type and read the value user typed into a variable. Example: User type 4.137, the program will read 4.137 and assign it to a variable A. I try to find the syntax to do this on VB.net but I have no luck finding the right syntax to read the value. I using VS 2005.
This is kind of two questions (one more specific than the other).If I have a method like this:[code]Can I qualify Foo against another type (for instance can I require that Foo be a String that also implements IInterface?).I'm imagining something vaguely similar to this:[code]Additionally, is there any way to qualify the Type parameter?For instance, can I require that the Type I take as a parameter is of a particular class tree?I should mention that I am using this in the context of a property of an attribute so the class declaration itself cannot be generic (this is purely focused on qualifying a method parameter rather than typing a class and its methods).
This is the whole Class..The function works like this, [code] Now, when I load a big text with higlighted words in there, and when I try to type, it goes like up and down fast for 5 minutes for stupid reason. I don't know why, whats wrong. [code]
I did create a XDateTime class that is able to handle inaccurate date and time. This class has all the CType operators required to convert to and from a string and it has been fully tested during the last months.
I'm trying to create a function to parse out all values in a multidimensional Array with all but one dimension given. The details are not relevant, but for this function I need to return an one-dimensional Array containing values of the same type the original multidimensional Array has.To pass any Array with any dimension to my function, I declared the type of this parameter as Array. However, how would I create a new Array of that specific type (e.g. Integer)?Currently I have the following code:
Function GetRow(ByVal arr As Array) As Array Dim result As (...) 'This should be Integer() if arr contains Integers, etc. Return result
I need type parameter overloading as such:[code..]
so that i can New Map(Of Human) and the compiler will automatically match it to Public Class Map(Of TKey, TValue) and if i new Map(Of String) the compiler will automatically match it to Public Class Map(Of TKey As IEquatable(Of TKey), TValue) (since String is an IEquatable(Of String))
Right now my solution is to give the class different names as such:[code...]
im making a function that disables controls except for a type of control i want to specify. how would I make the header of this procedure is my procedure should capture a control and a object of any type If I would call modUtilities.DisableControls(Panel_OwnerInfo, CheckBox_HasCell) is should disable all the controls inside Panel_OwnerInfo except for the CheckBox_HasCell Now I've done the disabling thing, but how would I specify the procedure parameter to recieve a class type?
I have a base class with a static function that returns a typed dataset. I have several classes that inherit the base class with a non-static function that returns the same typed dataset. On these methods I get the 'Return type of parameter yadda is not CLS-compliant' I don't understand where this is coming from. I have non unsigned integers/etc. in this dataset.
I'd like to auto-register the common/simple services in my unity container. I think the cleanest way to do this would be via a custom atribute.I can then examine all the (abstract) classes in an assembly and register those types with unity.The piece of information I'm missing is the interface(s) that the class wants to be registered against
eg:
Public Class AutoRegisterAttribute Public Property ForInterface As System.Type Public Sub New(ForInterface As System.Type)
[code]....
Note, I don't just want to find any class it implements as shown with IDisposableI've tried doing this using generics (generics can't inherit from Attribute), with a Type Parameter (Passing in IEngine.GetType results in a "Constant expression is required")
I have a TreeView, which contains nodes. When a user clicks on a node, corresponding CrystalReport document should be created and displayed.For example, names of my nodes are: "PeriodReport1", "PeriodReport2", "PeriodReport3". My CrystalReport documents are named same: "PeriodReport1", "PeriodReport2", "PeriodReport3".How can I create and display right type of crystal reports document? I could do something like this:
I have a datagridview with a checkbox column. I'm trying to update data in the dataset but I keep getting this error: Conversion from string "ExtendDate" to type 'Integer' is not valid.The parameter type for ExtendDate is boolean but i'm not sure if that's the correct type.
Code: Dim Col11 As New DataGridViewCheckBoxColumn With Col11 .DataPropertyName = "ExtendDate" .HeaderText = "Extend Date"
