Is there a better/best way to determine the type of a passed object in VB.NET?

Question

I am still developing this function, but here is what I am intending it to do. This function will accept an Object, then try to determine its type. There are a specific set of types I am looking for: Integer, Boolean, Date, String. What I have so far is pretty privative, but it seems to be working so far:

Private Function DataType(ByVal entry As Object) As ValueType
    Try
        If IsNumeric(entry) Then
            If Integer.Parse(entry) Then
                Return ValueType.Number
            End If
        End If
    Catch
    End Try

    Try
        If Boolean.Parse(entry) Then
            Return ValueType.Boolean
        End If
    Catch
    End Try

    Try
        If Not Date.Parse(entry) = Nothing Then
            Return ValueType.Date
        End If
    Catch
    End Try

    Return ValueType.Text
End Function

Answer 1

I would suggest using TypeOf instead of Parse or TryParse

  If  TypeOf entry Is Integer Then ...

Answer 2

You'll have to decide whether you will accept "42" to be an integer. The object type is still String!

The try-blocks and additional checking with IsNumeric can be removed anyway - Just use the TryParse-Functions

    Dim IntResult As Integer

    If Integer.TryParse("42", IntResult) Then
        ' Parsing succeeded - Result is stored in IntResult '
    Else
        ' Failed! '
    End If

When the types can be checked at compile-time, you could use parameter overloading.

Answer 3

I am a C# developer and I don't fully unterstand your code, but I would use a dictionary to map between the type of an object and something else - I assume you return a enum value. Here is a C# example. In real code the dictionary should probably not be build on every method call.

public enum ValueType
{
    Unknown, Number, Boolean, Date, String
}

public static ValueType DataType(Object o)
{
    Dictionary<Type, ValueType> map =
        new Dictionary<Type, ValueType>
            {
                {typeof (Int32), ValueType.Number},
                {typeof (Int64), ValueType.Number},
                {typeof (Decimal), ValueType.Number},
                {typeof (Single), ValueType.Number},
                {typeof (Double), ValueType.Number},
                {typeof (Boolean), ValueType.Boolean},
                {typeof (DateTime), ValueType.Date},
                {typeof (String), ValueType.String}
            };

    if ((o == null) || (!map.ContainsKey(o.GetType())))
    {
        return ValueType.Unknown;
    }
    else
    {
        return map[o.GetType()];
    }
}

I had a second look and it looks like you are trying to determine the type of information stored in a string by parsing it - in this case the above won't help.