I have a class module in my App_code folder.
Private _connection As MySqlConnection
Private _connStr As String
Public Function Connect(dbName As String) As Boolean
Try
_connStr = "Database=" & dbName & ";" & _
"Data Source=192.16.0.1;" & _
"User Id=user;Password=pass"
_connection = New MySqlConnection(_connStr)
_connection.Open()
_connection.Close()
Return True
Catch ex As Exception
_connection = Nothing
Return False
End Try
Return False
End Function
I usually program in webform apps. Why can't I access this function from my aspx code behind pages? I added the import statement for the class. If i make that function shared I cant have those private variables.
I call the function in my aspx lik so;
If Connect(dbName) then....
That gets me an error "non shared member requires an object reference"
You need to add the keyword "Shared" to the method signature, like so:
Private Shared _connection As MySqlConnection
Private Shared _connStr As String
Public Shared Function Connect(dbName As String) As Boolean
This is because otherwise you have instance class members, not static members. The compiler error message is quite self-explanatory.
if you look at this example works:
Public Shared Function example123(ByVal USER As Integer, ByVal Section As String, ByVal ACTION As String) As Boolean
you assign a function shared so you can see it from outside the class
I hope you work
Related
Alright so I'm building an ASP.NET web site, currently creating the log in form however I keep getting an error that I am unable to attach a SQL Server file.
I did some research and found I needed to create an app_data folder in my directory which I did, and in that folder now there are 3 .mdf files (SQL Server primary data files) which I cannot open in SQL Server Management Studio.
Looks like similar problems are solved by fixing a connection to a SQL Server. However, in my web site I don't have a connection to an SQL Server declared so why is there a SQL Server error? Also attaching the function that is being called
Protected Sub Login1(sender As Object, e As System.EventArgs) Handles loginForm.LoggingIn
Dim bolloginCheck As Boolean
ScriptManager.RegisterStartupScript(Me, Me.GetType(), "alertMessage", "alert(' " & loginForm.UserName.Trim() & " - " & loginForm.Password.Trim() & " ');", True) 'displays localhostsays : called fomrcode-behind directly!
bolloginCheck = _client.Verify_Login(loginForm.UserName, loginForm.Password)
If bolloginCheck = True Then
'set user name Or session variable, adjust to true And authenticated
Response.Redirect("https://www.google.com")
Else
loginForm.FailureText = "Unable to login, please review your login credentials."
End If
End Sub
Public Function Verify_Login(strUsername As String, strPassword As String) As Boolean Implements IService.Verify_Login
Return True
End Function
<ServiceContract()>
Public Interface IService
''WEBSITE FUNCTIONS''
<OperationContract()>
Function Verify_Login(uname As String, pword As String) As Boolean
End Interface
<DataContract()>
Public Class CompositeType
<DataMember()>
Public Property BoolValue() As Boolean
<DataMember()>
Public Property StringValue() As String
End Class
Public Class Service
Implements IService
Public Sub New()
End Sub
Public Function Verify_Login(strUsername As String, strPassword As String) As Boolean Implements IService.Verify_Login
Return True
End Function
End Class
Error:
An attempt to attach an auto-named database for file C:\Users\Dewy\Desktop\TestWebSite\App_Data\aspnetdb.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
Hi I need to create a class for return the data in WCF service. I followed the web at 5 simple steps to create your first RESTful service. However I get the error for . I searched the web and add the System.Runtime.Serialization.DataContractSerializer, Would someone tell me what should do. I am using VS2015 as the tool to build it. Thanks.
Imports System.Runtime.Serialization
Imports System.Collections.Generic
Imports System.Runtime.Serialization.DataContractSerializer
<DataContract>
Public Class Locations
<DataMember>
Public Property LocationName As String
<DataMember>
Public Property LocationID As Integer
End Class
Could you please share the error details with me?
As you know, we usually use the datacontract to transmit the complex data type which could be recognized by the client-side and server-side. so that the data could be serialized and transmitted normally between different platforms.
For the restful web service in WCF, we need to use the Webhttpbinding build the data channel and add the Webhttpbehavior to the service endpoint.
I have made a demo, wish it is useful to you.
Server-side.
Imports System.Runtime.Serialization
Imports System.ServiceModel
Imports System.ServiceModel.Description
Imports System.ServiceModel.Web
Module Module1
Sub Main()
Dim uri As New Uri("http://localhost:900")
Dim binding As New WebHttpBinding()
binding.CrossDomainScriptAccessEnabled = True
binding.Security.Mode = WebHttpSecurityMode.TransportCredentialOnly
binding.Security.Transport.ClientCredentialType = HttpClientCredentialType.None
Using sh As New ServiceHost(GetType(MyService), uri)
Dim se As ServiceEndpoint = sh.AddServiceEndpoint(GetType(IService), binding, uri)
se.EndpointBehaviors.Add(New WebHttpBehavior())
sh.Open()
Console.WriteLine("Service is ready")
Console.ReadLine()
sh.Close()
End Using
End Sub
<ServiceContract([Namespace]:="mydomain")>
Public Interface IService
<OperationContract>
<WebGet(ResponseFormat:=WebMessageFormat.Json)>
Function SayHello() As List(Of Product)
End Interface
Public Class MyService
Implements IService
Public Function SayHello() As List(Of Product) Implements IService.SayHello
Dim result = New List(Of Product)() From {
New Product With {
.Id = 1,
.Name = "Apple"
},
New Product With {
.Id = 2,
.Name = "Pear"
}
}
Return result
End Function
End Class
<DataContract([Namespace]:="mydomain")>
Public Class Product
<DataMember>
Public Property Id() As Integer
<DataMember>
Public Property Name() As String
End Class
End Module
Client.
$(function(){
$.ajax({
type:"GET",
url:"http://10.157.18.188:900/sayhello",
dataType:"jsonp",
success:function(d){
$.each(d,function(i,o){
console.log(o.Id);
console.log(o.Name);
})
}
})
})
Result.
Here is an official sample
https://learn.microsoft.com/en-us/dotnet/framework/wcf/feature-details/how-to-create-a-basic-wcf-web-http-service
I want to test a function which is in a web page. Do I have way to use System.Web.UI.Page in a console application and put something in Session and test this way?
I created a test class and to inherit the Page but I could not put Session in it. When I type "myPage." as show below, I do not see anything come out after "."
<TestClass()> Public Class UnitTest2
Inherits System.Web.UI.Page
Dim myPage = New System.Web.UI.Page
myPage.
End Class
Please help!
Update: Below code seemed to pass the compiler
<TestClass()> Public Class UnitTest2
<TestMethod()>
Public Sub TestCheckRules()
Dim myPage As testWebPage = New testWebPage
myPage.testSession()
End Sub
End Class
Public Class testWebPage
Inherits System.Web.UI.Page
Public Sub New()
End Sub
Public Sub testSession()
Dim firstName As String = "John"
Dim lastName As String = "Smith"
Dim city As String = "Seattle"
Session("FirstName") = firstName
Session("LastName") = lastName
Session("City") = city
End Sub
End Class
Then when I ran I got the following error:
An exception of type 'System.Web.HttpException' occurred in System.Web.dll but was not handled in user code
Additional information: Session state can only be used when enableSessionState is set to true, either in a configuration file or in the Page directive. Please also make sure that System.Web.SessionStateModule or a custom session state module is included in the \\ section in the application configuration.
I'm not sure if this is possible but I would like to associate a class name reference to a shared member method / property / variable. Consider:
Public Class UserParameters
Public Shared Reference As Object
Public Shared Function GetReference() As Object
Return Reference
End Function
End Class
In another part of the program I would like to simply call UserParameters and have it return Reference either by aliasing GetReference or the variable directly.
I am trying to emulate the Application, Request, or Session variable:
Session(0) = Session.Item(0)
Any suggestions would be greatly appreciated.
You can't return an instance member from a static method directly (the static method can't access instance members because it isn't instantiated with the rest of the class, only one copy of a static method exists).
If you need to setup a class in such a way that you can return an instance from a static method you would need to do something similar to the following:
Public Class SampleClass
Private Sub New()
'Do something here
End Sub
Public Shared Function GetSample() As SampleClass
Dim SampleClass As SampleClass
SampleClass = New SampleClass
SampleClass.Sample = "Test"
Return SampleClass
End Function
Private _SampleString As String
Public Property Sample As String
Get
Return _SampleString
End Get
Private Set(ByVal value As String)
_SampleString = value
End Set
End Property
End Class
Public Class SampleClass2
Public Sub New()
'Here you can access the sample class in the manner you expect
Dim Sample As SampleClass = SampleClass.GetSample
'This would output "Test"
Debug.Fail(Sample.Sample)
End Sub
End Class
This method is used in various places in the CLR. Such as the System.Net.WebRequest class. where it is instantiated in this manner in usage:
' Create a request for the URL.
Dim request As WebRequest = WebRequest.Create("http://www.contoso.com/default.html")
I have had several occasions recently to access a specific class several times over a relatively small time frame.
So I've been storing the value of the class in Session and trying to access it on page load, if it's not available creating a new instance and storing that in session.
So instead of constantly replicating the same code for different classes on different pages I'm trying to create an extension method to do this for me.
I want to use it like this
Dim objName as MyClass
objName.SessionSingleton()
So far this is what I have for my extension method:
<Extension()> _
Public Sub SessionSingleton(ByRef ClassObject As Object)
Dim objType As Type = ClassObject.GetType
Dim sessionName As String = objType.FullName
If TypeOf HttpContext.Current.Session(sessionName) Is objType And HttpContext.Current.Session(sessionName) <> "" Then
ClassObject = HttpContext.Current.Session(sessionName)
Else
Dim singleton As Object = New objType???????
HttpContext.Current.Session(sessionName) = singleton
ClassObject = singleton
End If
End Sub
I'm stuck on what to do when I make my new instance of my class (it would have to have a New() sub)
I'm not sure where to go from here... or even if this is the best way to do it.
I figured it out and am posting my code for reference. While digging thru pages about Class/Object Factories (thanks RBarry) I found several references to Activator.CreateInstance() in the System.Reflection Class I came up with this.
Imports Microsoft.VisualBasic
Imports System.Runtime.CompilerServices
Imports System.Reflection
Public Module enviornmentUtilities
<Extension()> _
Public Function SessionSinglton(ByVal objType As Type) As Object
Dim sessionName As String = objType.FullName.ToString
If Not HttpContext.Current.Session(sessionName) Is Nothing Then
HttpContext.Current.Trace.Write(HttpContext.Current.Session(sessionName).ToString)
Return HttpContext.Current.Session(sessionName)
Else
Dim ss = Activator.CreateInstance(objType)
HttpContext.Current.Session(sessionName) = ss
Return ss
End If
End Function
End Module
This will let you create a session based singleton from any class that does not require parameters in the new method (which isn't required for this to work)
To test I made a simple Class:
Public Class HasNew
Public FreshInstance As Boolean = True
Public Sub New()
HttpContext.Current.Trace.Warn("This Class has a new method")
End Sub
Public Sub CheckFreshness()
If FreshInstance Then
HttpContext.Current.Trace.Warn("Fresh HasNew Instance")
FreshInstance = False
Else
HttpContext.Current.Trace.Warn("NotFresh HasNew Instance")
End If
End Sub
Public Shared Function type() As Type
Return GetType(HasNew)
End Function
Public Shared Function SessionSinglton() As HasNew
Return GetType(HasNew).SessionSinglton
End Function
End Class
You'll notice the two Public Shared Methods type() and SessionSinglton which calls the above extension method.
With those two functions added we have three ways to initiate the Session Singlton demonstrated here:
Dim HN As HasNew
HN = HasNew.SessionSinglton
HN.CheckFreshness()
HN = HasNew.type.SessionSinglton
HN.CheckFreshness()
HN = GetType(HasNew).SessionSinglton
HN.CheckFreshness()
The Trace Output for this file is as follows:
This Class has a new method
Fresh HasNew Instance
NotFresh HasNew Instance
NotFresh HasNew Instance
The classes new() method is accessed on the first call to the SessionSinglton method and subsequent calls reflect that the instance is in fact being pulled from memory.
I hope this helps someone else in the future.
If you used generics you could just do New T(). Also your SessionSingleton returns "object" type, requiring casting. I did not test this but it should work.
Imports Microsoft.VisualBasic
Imports System.Runtime.CompilerServices
Imports System.Reflection
Public Module enviornmentUtilities
<Extension()> _
Public Function SessionSinglton(Of T As {Class, New})(ByVal obj As T) As T
Dim sessionName As String = obj.GetType.Name
If Not HttpContext.Current.Session(sessionName) Is Nothing Then
HttpContext.Current.Trace.Write(HttpContext.Current.Session(sessionName).ToString)
Return HttpContext.Current.Session(sessionName)
Else
Dim ss = New T()
HttpContext.Current.Session(sessionName) = ss
Return ss
End If
End Function
End Module