/// <summary>
/// Resolves the value for the given expression.
/// </summary>
/// <param name="context">The render context.</param>
/// <param name="templateData">The template data.</param>
/// <param name="expression">The expression.</param>
/// <param name="isVariableLookup">True if this is a variable lookup, otherwise false.</param>
/// <returns>The resolved value.</returns>
public object ResolveValue(RenderContext context, TemplateData templateData, string expression, bool isVariableLookup)
{
if (isVariableLookup && !string.IsNullOrEmpty(expression) && !expression.StartsWith("root."))
{
return(context.GetVariable(expression));
}
if (isVariableLookup && !string.IsNullOrEmpty(expression) && expression.StartsWith("root."))
{
context = context.RootRenderContext ?? context;
templateData = context.TemplateData;
expression = expression.Substring(5);
}
var modelMetadata = ExpressionMetadataProvider.FromStringExpression(expression, templateData, context.ModelMetadataProvider);
if (modelMetadata == null || !modelMetadata.Valid)
{
if (context.UnknownValueResolver != null)
{
return(context.UnknownValueResolver(expression));
}
return(null);
}
return(modelMetadata.Model);
}
/// <summary>
/// Resolves the value for the given expression.
/// </summary>
/// <param name="context">The render context.</param>
/// <param name="templateData">The template data.</param>
/// <param name="expression">The expression.</param>
/// <param name="isVariableLookup">True if this is a variable lookup, otherwise false.</param>
/// <returns>The resolved value.</returns>
public static object ResolveValue(RenderContext context, TemplateData templateData, string expression, bool isVariableLookup)
{
if (isVariableLookup && !string.IsNullOrEmpty(expression) && !expression.StartsWith("root."))
{
return context.GetVariable(expression);
}
if (isVariableLookup && !string.IsNullOrEmpty(expression) && expression.StartsWith("root."))
{
context = context.RootRenderContext ?? context;
templateData = context.TemplateData;
expression = expression.Substring(5);
}
var modelMetadata = ExpressionMetadataProvider.FromStringExpression(expression, templateData, context.ModelMetadataProvider);
if (modelMetadata == null)
{
return null;
}
return modelMetadata.Model;
}
