FieldMetadata CalcExpression(String expression)
{
if (String.IsNullOrEmpty(expression))
{
return(null);
}
if (expression.StartsWith("Parent."))
{
return(null);
}
if (expression.StartsWith("."))
{
return(null); // inner context (DataGrid ?)
}
if (expression.Contains(".$selected"))
{
return(null);
}
if (expression.StartsWith("-"))
{
expression = expression.Substring(1);
}
var segments = expression.Split('.');
var currentType = _mm["TRoot"];
var len = segments.Length;
for (var i = 0; i < len; i++)
{
var seg = segments[i];
if (seg == "Root")
{
currentType = _mm["TRoot"];
continue;
}
if (!currentType.ContainsKey(seg))
{
throw new TypeCheckerException($"Xaml. Field not found '{expression}'");
}
if (i != len - 1)
{
var typeName = currentType[seg];
var typeMeta = _mm.FindType(typeName.Type.RealType);
currentType = typeMeta ?? throw new TypeCheckerException($"Xaml. Field not found '{expression}'");
}
else
{
return(currentType[seg]);
}
}
return(null);
}