IEnumerator IEnumerable vb to C#

Question

Hello everyone i'm new to c# language i was use vb.net, in below what is the error with this code and why, thank you

vb.net code
Class SplitString
Implements IEnumerable
Implements IEnumerator

Private currentPosition As Integer = 0
Private m_Sentence As String
Property Sentence() As String
    Get
        Return m_Sentence
    End Get
    Set(ByVal Value As String)
        m_Sentence = Value
        Me.Reset()
    End Set
End Property

Public ReadOnly Property Current As Object Implements IEnumerator.Current
    Get
        Dim counter As Integer
        Dim tmpLength As Integer = 0
        For counter = Me.currentPosition To Me.Sentence.Length - 1
            If Me.Sentence.Chars(counter) = " "c Then
                Exit For
            Else
                tmpLength += 1
            End If
        Next
        Current = Me.Sentence.Substring(Me.currentPosition, tmpLength) ' ok 
        Me.currentPosition += tmpLength + 1
    End Get
End Property

Public Function MoveNext() As Boolean Implements IEnumerator.MoveNext
    If Me.currentPosition > Me.Sentence.Length - 1 Then
        Me.Reset()
        Return False
    Else
        Return True
    End If
End Function

Public Sub Reset() Implements IEnumerator.Reset
    Me.currentPosition = 0
End Sub

Public Function GetEnumerator() As IEnumerator Implements IEnumerable.GetEnumerator
    Return Me
End Function
End Class

but when i try this code to c# i get Error

c# code
class SplitString:IEnumerable,IEnumerator
{
    private int currentPosition = 0;
    private string m_Sentence;
    public string Sentence
    {
        get { return m_Sentence; }
        set
        {
            m_Sentence = value;
            this.Reset();
        }
    }
    public IEnumerator GetEnumerator()
    {
        return this;
    }


    public object Current
    {
        get
        {
            int counter = 0;
            int tmpLength = 0;
            for (counter = this.currentPosition; counter <= this.Sentence.Length - 1; counter++)
            {
                if (this.Sentence[counter] == ' ')
                {
                    break; 
                }
                else
                {
                    tmpLength += 1;
                }
            }
            Current = this.Sentence.Substring(this.currentPosition, tmpLength); // Error
            this.currentPosition += tmpLength + 1;
            return functionReturnValue;
        }
    }
    public bool MoveNext()
    {
       if (this.currentPosition > this.Sentence.Length-1)
       {
           this.Reset();
           return false;
       }
       else
       {
           return true;
       }
    }

    public void Reset()
    {
        this.currentPosition=0;
    }
}

error: Property or indexer ‘Example.splitstring.current’ cannot ve assigned to – it is read only

Answer 1

This

Current = Me.Sentence.Substring(Me.currentPosition, tmpLength) ' ok 

is the "old" VB way of setting a return value in a method without using the Return keyword. In general, the following VB code

    myMethodName = ...
    ...some other code...
End Function

can be rewritten as

    Dim someTempVariable = ...
    ...some other code...
    Return someTempVariable
End Function

(as long as some other code does not exit the method).

The same is true for properties. Thus, we first rewrite your old VB code to new VB code:

        ...
    Next
    Dim returnValue = Me.Sentence.Substring(Me.currentPosition, tmpLength) 
    Me.currentPosition += tmpLength + 1
    Return returnValue
End Get

and now the translation to C# should be obvious.