Why can't value of type List(Of Integer) be converted to Integer when sending value to WCF service?

问题

Client code:

Public Sub sendEmpValue(name As String, value As List(Of Integer))
    Dim serviceObject As New Service.GetEmployeeClient
    serviceObject.DoWork(name, value)** getting error at the value**
End Sub

Service code:

Sub DoWork(name As String, value As List(Of Integer)) Implements IGetEmployee.DoWork
End Sub

回答1:

The DoWork method expects an Integer() which is an array of integers.

The List(Of T) class has got a function called ToArray() which will return the list as an array. Call that and it should work.

serviceObject.DoWork(name, value.ToArray())

Read more about arrays on the MSDN documentation.

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According to this answer when using WCF a List(Of T) is converted into an array on the clientside, which is why the DoWork method wants an array instead of a List(Of Integer) as you've specified. This behaviour can apparently be modified though.

来源：https://stackoverflow.com/questions/40692142/why-cant-value-of-type-listof-integer-be-converted-to-integer-when-sending-va