public static bool IsPropertyReadExpression(LambdaExpression instance, LambdaExpression prop, string altInstanceArgName = default, string altPropArgName = default)
{
instance.EnsureNotNull(nameof(instance));
prop.EnsureNotNull(string.IsNullOrEmpty(altPropArgName) ? nameof(prop) : altPropArgName);
//
if (prop.Body is MemberExpression memberExpr)
{
var propertyMember = memberExpr.Member as PropertyInfo;
if (propertyMember == null || !propertyMember.IsNonStaticRead())
{
return(false);
}
Type propertyAccessInstanceType;
if (memberExpr.Expression is ConstantExpression accessConstantExpr)
{
propertyAccessInstanceType = accessConstantExpr.Type;
}
else if (memberExpr.Expression is MemberExpression accessMemberExpr)
{
var accessMemberField = accessMemberExpr.Member as FieldInfo;
if (accessMemberField == null)
{
return(false);
}
propertyAccessInstanceType = accessMemberField.FieldType;
}
else if (memberExpr.Expression is ParameterExpression accessParameterExpr)
{
propertyAccessInstanceType = accessParameterExpr.Type;
}
else
{
return(false);
}
if (instance.ReturnType.IsAssignableFrom(propertyAccessInstanceType) && propertyMember.DeclaringType.IsAssignableFrom(instance.ReturnType))
{
return(true);
}
}
return(false);
}
// TODO: Put strings into the resources.
//
public static MemberInfo ExtractMember(LambdaExpression expr, string altExprArgName = default)
{
var argName = string.IsNullOrEmpty(altExprArgName) ? nameof(expr) : altExprArgName.FmtStr().G();
expr.EnsureNotNull(argName);
//
var exprBody = expr.Body;
if (exprBody is MemberExpression bodyAsMemberExpr)
{
return(bodyAsMemberExpr.Member);
}
else if (exprBody is MethodCallExpression bodyAsMethodCallExpr)
{
return(bodyAsMethodCallExpr.Method);
}
else
{
throw new ArgumentException(message: $"Specified expression does not access a member and doesn't access a method.{Environment.NewLine}\tExpression:{expr.FmtStr().GNLI2()}", paramName: argName);
}
}