/// <summary>
/// Given a targeted binding expression (in the form "foo->bar"), this method extracts the target name, target type, and expression text.
/// </summary>
private Boolean GetExpressionTargetInfo(ExpressionCompilerState state, DataSourceWrapperInfo dataSourceWrapperInfo,
XObject source, ref String expText, out String expTarget, out Type expTargetType)
{
const string TargetExpressionDelimiter = "->";
var expOriginal = expText;
var delimiterIndex = expText.IndexOf(TargetExpressionDelimiter);
if (delimiterIndex >= 0)
{
var expPartTarget = expText.Substring(0, delimiterIndex);
var expPartText = expText.Substring(delimiterIndex + TargetExpressionDelimiter.Length);
var matchCandidates = (from element in dataSourceWrapperInfo.DataSourceDefinition.Definition.Descendants()
where (String)element.Attribute("Name") == expPartTarget
select element).ToList();
if (matchCandidates.Count == 0)
{
throw new BindingExpressionCompilationErrorException(source, dataSourceWrapperInfo.DataSourceDefinition.DefinitionPath,
CompilerStrings.ExpressionTargetIsNotFound.Format(expPartTarget));
}
if (matchCandidates.Count > 1)
{
throw new BindingExpressionCompilationErrorException(source, dataSourceWrapperInfo.DataSourceDefinition.DefinitionPath,
CompilerStrings.ExpressionTargetIsAmbiguous.Format(expPartTarget));
}
var match = matchCandidates.Single();
var matchName = match.Name.LocalName;
expText = expPartText;
expTargetType = ExpressionCompiler.GetPlaceholderType(dataSourceWrapperInfo.DataSourceType, matchName);
if (expTargetType == null && !state.GetKnownType(matchName, out expTargetType))
{
throw new BindingExpressionCompilationErrorException(source, dataSourceWrapperInfo.DataSourceDefinition.DefinitionPath,
CompilerStrings.ExpressionTargetIsUnrecognizedType.Format(expOriginal, matchName));
}
expTarget = String.Format("__UPF_GetElementByName<{0}>(\"{1}\").", GetCSharpTypeName(expTargetType), expPartTarget);
return(true);
}
expTarget = default(String);
expTargetType = dataSourceWrapperInfo.DataSourceType;
return(false);
}