How to Sort Listview Columns Containing Strings & Integers?

Question

General Information

I have a ListView containing multiple columns. I have used a Microsoft Method to sort my ListView Columns . The ListView is populated by a SQL Query which correctly sorts Strings and Integers together ( code shown below ). For Example:

String & Integer Sorting Problem

The following JobNumber strings are considered as sorted

"10", "1", "2", "3"

Using my SQL Query, they will become

"1", "2", "3", "10"

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SQL String & Integer Sorter

Here is the Query I use to sort Strings and Integers correctly

SELECT PK_BillHeader, JobNumber, Description
FROM dbo.BillHeaders 
ORDER BY Case IsNumeric(JobNumber) 
    When 1 Then Replicate('0', 50 - Len(JobNumber)) + JobNumber 
        Else JobNumber 
    End

This enters zeros until it gets the maximum length of my SQL column (50 chars) minus the JobNumber 's current length. That way, everything is considered as a string (including integers) which can then be sorted out correctly.

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My Problem

When I click on the ListView Column Header (causing it to sort), it stops sorting the strings and integers correctly as it did with my SQL query. Instead, it sorts everything as a string which replicates my " String & Integer " sort problem once more ... What is more, if I have decimal values ( second picture ), it sorts them out pretty weird ( see my compare code )

Compare Code

Public Function [Compare](ByVal x As Object, ByVal y As Object) As Integer Implements IComparer.Compare
        Dim xItem As clsSortWrapper = CType(x, clsSortWrapper)
        Dim yItem As clsSortWrapper = CType(y, clsSortWrapper)

        Dim xText As String = xItem.sortItem.SubItems(xItem.sortColumn).Text
        Dim yText As String = yItem.sortItem.SubItems(yItem.sortColumn).Text

        If Decimal.TryParse(xText, vbNull) Then xText = xText.PadLeft(10, "0"c)
        If Decimal.TryParse(yText, vbNull) Then yText = yText.PadLeft(10, "0"c)
        Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)
    End Function

Is there a simpler way to acheive my result of sorting a ListView with Strings and Integers?

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Note:

I omitted posting the ListView Sort code here because it would've clustered the post quite a bit. I provided the link which explains it thoroughly.

Answer 1

Approach #1: Codesnippet from Natural Comparer Whole source code is here

This will sort the way you described in your question, also supporting roman values ('D', 'X', etc.).

int System.Collections.Generic.IComparer<string>.Compare(string string1, 
                                                 string string2)
{
  mParser1.Init(string1);
  mParser2.Init(string2);
  int result;
  do
  {
    if (mParser1.TokenType == TokenType.Numerical & 
                 mParser2.TokenType == TokenType.Numerical)
      // both string1 and string2 are numerical 
      result = decimal.Compare(mParser1.NumericalValue, mParser2.NumericalValue);
    else
      result = string.Compare(mParser1.StringValue, mParser2.StringValue);
    if (result != 0) return result;
    else
    {
      mParser1.NextToken();
      mParser2.NextToken();
    }
  } while (!(mParser1.TokenType == TokenType.Nothing & 
             mParser2.TokenType == TokenType.Nothing));  
  return 0; //identical 
}

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Approach #2: Easy, customized Comparer (Without Roman values)

class MyComparer : IComparer<string>
{
    public int Compare(string x, string y)
    {
        int xVal, yVal;
        var xIsNumeric = int.TryParse( x, out xVal );
        var yIsNumeric= int.TryParse( y, out yVal );

        if (xIsNumeric && yIsNumeric)
            return xVal.CompareTo(yVal);
        if (!xIsNumeric && !yIsNumeric)
            return x.CompareTo(y);
        if (xIsNumeric )           
            return -1;
        return 1;   
    }
}

Answer 2

Here's another way. In your Sort code pad the strings with 0's when you call CompareTo.

If Integer.TryParse(xText, VBNull) Then
      xText = xText.PadLeft(6, "0"c)
End If
If Integer.TryParse(yText, VBNull) Then
      yText = yText.PadLeft(6, "0"c)
End If
Return xText.CompareTo(yText) * IIf(Me.ascending, 1, -1)

This way "11004" will be compared as "011004" and appear before "110030", but the padding is only for comparison, the value will still be displayed as "11004".

UPDATE:

Normal strings will be sorted without padding now.