public override object ProvideValue(IServiceProvider serviceProvider)
{
if (Expression == null)
{
return(0.0);
}
var nameResolver = (IXamlNameResolver)serviceProvider;
if (nameResolver == null)
{
throw new ArgumentException("Missing IXamlNameResolver", "context");
}
List <string> unknownNameList;
var nameValueTable = ExpressionServices.GetNameValueTable(nameResolver, Expression, out unknownNameList);
if (unknownNameList != null && unknownNameList.Count > 0)
{
object fixup = nameResolver.GetFixupToken(unknownNameList);
return(fixup);
}
// if we have the values of all the names,
// hand it to the expresssion parser and let 'er rip!
//
MathExpressionParser parser = new MathExpressionParser(nameValueTable);
Double number = parser.Parse(Expression);
return(number);
}
public override object ConvertFrom(ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
{
string text = (string)value;
if (text == null)
{
throw new ArgumentException("Missing String Value", "value");
}
var nameResolver = (IXamlNameResolver)context;
if (nameResolver == null)
{
throw new ArgumentException("Missing IXamlNameResolver", "context");
}
var names = new List <string>();
var scanner = new MathExpressionScanner(text);
foreach (MathExpressionToken scannerTok in scanner.Scan())
{
switch (scannerTok.TokenType)
{
case MathTokenType.Name:
if (!names.Contains(scannerTok.Name))
{
names.Add(scannerTok.Name);
}
break;
}
}
var unknownNameList = new List <string>();
var nameValueTable = ExpressionServices.GetNameValueTable(nameResolver, text, out unknownNameList);
if (unknownNameList != null && unknownNameList.Count > 0)
{
object fixup = nameResolver.GetFixupToken(unknownNameList);
return(fixup);
}
// if we have the values of all the names,
// hand it to the expresssion parser and let 'er rip!
//
MathExpressionParser parser = new MathExpressionParser(nameValueTable);
Double number = parser.Parse(text);
return(number);
}