/// <summary>
/// Check a compare result against a filter type. We use
/// the internal CompareData and ItemText methods to get
/// the correct text and perform the comparison using the
/// filter column datatype. The result from CompareData
/// is used to check against the Type of filtering applied.
/// The f (LVFFilter) has been prepared with all the data
/// about the filtering to be performed; column, text,
/// datatype, and filtering type by FilterBuild().
/// </summary>
/// <param name="r">Result -1/0/1</param>
/// <param name="f">LVFFilter</param>
/// <returns></returns>
private bool FilterCheck( ListViewItem i, LVFFilter f )
{
// get the result of the data type comparison
TypedColumnHeader header = this.Columns[ f.Column ] as TypedColumnHeader;
Debug.Assert( header != null );
int r = header.CompareData( header.GetData( i ), f.Data, _ignoreCase );
// compare the result against the filter comparison type
// a true result means that it passed filtering and should
// be left in the list of filtered items.
switch( f.Compare )
{
case LVFFilterType.Equal:
return ( r == 0 );
case LVFFilterType.NotEqual:
return ( r != 0 );
case LVFFilterType.Greater:
return ( r > 0 );
case LVFFilterType.GreaterEqual:
return ( r >= 0 );
case LVFFilterType.Less:
return ( r < 0 );
case LVFFilterType.LessEqual:
return ( r <= 0 );
default:
return ( r == 0 );
}
}
/// <summary>
/// Create a new filter entry for the given column. This
/// will replace/add a LVFFilter instance for the column
/// to the itm_filtrs array for use by FilterUpdate().
/// </summary>
/// <param name="c">Column number</param>
private void FilterBuild( int c )
{
// if this column exists in the filters array remove it
foreach( LVFFilter f in _filters )
if( f.Column == c )
{
_filters.Remove( f );
break;
}
// get the filter text for this column from the header
string s = _headerControl.Filter[ c ].Trim();
// if there is any size to it then create a new filter
if( s.Length > 0 )
{
// create a new filter object for this column
LVFFilter f = new LVFFilter();
f.Column = c;
f.Text = s;
f.Compare = LVFFilterType.Equal;
f.Type = _headerControl.DataType[ c ];
// check the first characters of the string to see
// if this is not a default equality comparison
switch( s[ 0 ] )
{
case '=':
f.Text = s.Remove( 0, 1 );
break;
case '!':
f.Compare = LVFFilterType.NotEqual;
f.Text = s.Remove( 0, 1 );
break;
case '>':
if( ( s.Length > 1 ) && ( s[ 1 ] == '=' ) )
{
f.Compare = LVFFilterType.GreaterEqual;
f.Text = s.Remove( 0, 2 );
}
else
{
f.Compare = LVFFilterType.Greater;
f.Text = s.Remove( 0, 1 );
}
break;
case '<':
if( ( s.Length > 1 ) && ( s[ 1 ] == '=' ) )
{
f.Compare = LVFFilterType.LessEqual;
f.Text = s.Remove( 0, 2 );
}
else
{
f.Compare = LVFFilterType.Less;
f.Text = s.Remove( 0, 1 );
}
break;
}
// add this to the array of filters
_filters.Add( f );
}
}
