Reference to a non-shared member requires an object reference

[lgdt]

Hi

I am new to VB - and this seems to work in C# - so can someone help me please because thisa is driving me mad.

I have created a function as a namespace within a VB class file in my .NET project (Content) as follows:

Imports System
Imports System.Data.SqlClient
Namespace Connections
Public Class SQLCons
 
Public Function LogonManager(ByVal ProcName As String, ByVal DSTabName As String, ByVal man_uname As String, ByVal man_password As String) As DataSet
 
Dim con As SqlConnection = New SqlConnection(ConfigurationSettings.AppSettings("ConnectionString"))
Dim SQLcom As SqlCommand = New SqlCommand(ProcName, con)
SQLcom.CommandType = CommandType.StoredProcedure
 
Dim DA As SqlDataAdapter = New SqlDataAdapter(SQLcom)
 
SQLcom.Parameters.Add("@man_uname", SqlDbType.NVarChar, 50, "man_uname").Value = man_uname
SQLcom.Parameters.Add("@man_password", SqlDbType.NVarChar, 50, "man_password").Value = man_password
 
SQLcom.Connection.Open()
SQLcom.ExecuteNonQuery()
SQLcom.Connection.Close()
 
Dim DS As DataSet = New DataSet
DA.Fill(DS, DSTabName)
 
Return DS
 
End Function
 
 
 
End Class
End Namespace

I use the import statement in the main calling class:

Imports System.Data.SqlClient
Imports System
Imports Content.Connections

However when I try to reference Class SQLCons in this class using these statements:

Dim DS As DataSet = New DataSet
DS = SQLCons.LogonManager("LogonManagers", "manager", txbxUName.Text.ToString(), txbxPword.Text.ToString())

I get the following compilation error:

Reference to a non-shared member requires an object reference (this refers to the reference to SQLCons.LogonManager)

Can anyone tell me what I'm doing wrong? As I say - this works OK in C# which is where I have lifted it from and tried to convert.

Thanks in advance.

 

[levyuk]

try this

[size=2][color=#0000ff]Imports[/color][/size][size=2] System.Data

[/size][size=2][color=#0000ff]Imports[/color][/size][size=2] System.Data.SqlClient

[/size][size=2][color=#0000ff]Public[/color][/size][size=2] [/size][size=2][color=#0000ff]Class[/color][/size][size=2] SQLCons

[/size][size=2][color=#0000ff]Public[/color][/size][size=2] [/size][size=2][color=#0000ff]Shared[/color][/size][size=2] [/size][size=2][color=#0000ff]Function[/color][/size][size=2] LogonManager([/size][size=2][color=#0000ff]ByVal[/color][/size][size=2] ProcName [/size][size=2][color=#0000ff]As[/color][/size][size=2] [/size][size=2][color=#0000ff]String[/color][/size][size=2], [/size][size=2][color=#0000ff]ByVal[/color][/size][size=2] DSTabName [/size][size=2][color=#0000ff]As[/color][/size][size=2] [/size][size=2][color=#0000ff]String[/color][/size][size=2], [/size][size=2][color=#0000ff]ByVal[/color][/size][size=2] man_uname [/size][size=2][color=#0000ff]As[/color][/size][size=2] [/size][size=2][color=#0000ff]String[/color][/size][size=2], [/size][size=2][color=#0000ff]ByVal[/color][/size][size=2] man_password [/size][size=2][color=#0000ff]As[/color][/size][size=2] [/size][size=2][color=#0000ff]String[/color][/size][size=2]) [/size][size=2][color=#0000ff]As[/color][/size][size=2] DataSet

[/size][size=2][color=#0000ff]Dim[/color][/size][size=2] con [/size][size=2][color=#0000ff]As[/color][/size][size=2] SqlConnection = [/size][size=2][color=#0000ff]New[/color][/size][size=2] SqlConnection(ConfigurationSettings.AppSettings([/size][size=2][color=#800000]"ConnectionString"[/color][/size][size=2]))

[/size][size=2][color=#0000ff]Dim[/color][/size][size=2] SQLcom [/size][size=2][color=#0000ff]As[/color][/size][size=2] SqlCommand = [/size][size=2][color=#0000ff]New[/color][/size][size=2] SqlCommand(ProcName, con)

SQLcom.CommandType = CommandType.StoredProcedure

[/size][size=2][color=#0000ff]Dim[/color][/size][size=2] DA [/size][size=2][color=#0000ff]As[/color][/size][size=2] SqlDataAdapter = [/size][size=2][color=#0000ff]New[/color][/size][size=2] SqlDataAdapter(SQLcom)

SQLcom.Parameters.Add([/size][size=2][color=#800000]"@man_uname"[/color][/size][size=2], SqlDbType.NVarChar, 50, [/size][size=2][color=#800000]"man_uname"[/color][/size][size=2]).Value = man_uname

SQLcom.Parameters.Add([/size][size=2][color=#800000]"@man_password"[/color][/size][size=2], SqlDbType.NVarChar, 50, [/size][size=2][color=#800000]"man_password"[/color][/size][size=2]).Value = man_password

SQLcom.Connection.Open()

SQLcom.ExecuteNonQuery()

SQLcom.Connection.Close()

[/size][size=2][color=#0000ff]Dim[/color][/size][size=2] DS [/size][size=2][color=#0000ff]As[/color][/size][size=2] DataSet = [/size][size=2][color=#0000ff]New[/color][/size][size=2] DataSet

DA.Fill(DS, DSTabName)

[/size][size=2][color=#0000ff]Return[/color][/size][size=2] DS

[/size][size=2][color=#0000ff]End[/color][/size][size=2] [/size][size=2][color=#0000ff]Function

End[/color][/size][size=2] [/size][size=2][color=#0000ff]Class

[/color][/size]

And then

[size=2][color=#0000ff]Dim[/color][/size][size=2] ds [/size][size=2][color=#0000ff]As[/color][/size][size=2] DataSet = [/size][size=2][color=#0000ff]New[/color][/size][size=2] DataSet

ds = LogonManager([/size][size=2][color=#800000]""[/color][/size][size=2], [/size][size=2][color=#800000]""[/color][/size][size=2], [/size][size=2][color=#800000]""[/color][/size][size=2], [/size][size=2][color=#800000]""[/color][/size][size=2])

[/size]

 

[jmcilhinney]

That code could not possibly work in C#. You have declared the LogonManager function as Public, so you must call it on an instance of the SQLCons class, e.g.

'Visual Basic
Dim mySQLCons As New SQLCons

Dim myDataSet As DataSet = mySQLCons.LogonManager(...)

//C#
SQLCons mySQLCons = new SQLCons;

DataSet myDataSet = mySQLCons.LogonManager(...);

not using just by using the class name. To be able to call a function using just the name of a class, it must be declared Shared in VB.NET or static in C#.

Also, what conventions you use is up to you, but LogonManager would be a more appropriate name for a property because it is a noun. Function names a normally verb oriented, like GetSomething or DoSomething. LogonManager sounds more like a thing than an action.