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How do I check if a property exists on a dynamic anonymous type in c#?

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How do I know if I have expandoObject property?

You can use this to see if a member is defined: var expandoObject = ...; if(((IDictionary<String, object>)expandoObject). ContainsKey("SomeMember")) { // expandoObject. SomeMember exists. }

How can you tell if a dynamic object is null?

dynamic post = SomeMethod(); if (post. modified == null){ //could return errors. } So, by checking a resultObj. ToString() == null I believe this may convert the dynamic to an object and therefore enable for true null checking.

What are difference between anonymous and dynamic types?

Anonymous type is a class type that contain one or more read only properties whereas dynamic can be any type it may be any type integer, string, object or class. Anonymous types are assigned types by the compiler. Anonymous type is directly derived from System.

What is an expandoObject?

The ExpandoObject class enables you to add and delete members of its instances at run time and also to set and get values of these members. This class supports dynamic binding, which enables you to use standard syntax like sampleObject. sampleMember instead of more complex syntax like sampleObject.


  public static bool IsPropertyExist(dynamic settings, string name)
  {
    if (settings is ExpandoObject)
      return ((IDictionary<string, object>)settings).ContainsKey(name);

    return settings.GetType().GetProperty(name) != null;
  }

  var settings = new {Filename = @"c:\temp\q.txt"};
  Console.WriteLine(IsPropertyExist(settings, "Filename"));
  Console.WriteLine(IsPropertyExist(settings, "Size"));

Output:

 True
 False

public static bool HasProperty(dynamic obj, string name)
{
    Type objType = obj.GetType();

    if (objType == typeof(ExpandoObject))
    {
        return ((IDictionary<string, object>)obj).ContainsKey(name);
    }

    return objType.GetProperty(name) != null;
}

if you can control creating/passing the settings object, i'd recommend using an ExpandoObject instead.

dynamic settings = new ExpandoObject();
settings.Filename = "asdf.txt";
settings.Size = 10;
...

function void Settings(dynamic settings)
{
    if ( ((IDictionary<string, object>)settings).ContainsKey("Filename") )
        .... do something ....
}

This works for anonymous types, ExpandoObject, Nancy.DynamicDictionary or anything else that can be cast to IDictionary<string, object>.

    public static bool PropertyExists(dynamic obj, string name) {
        if (obj == null) return false;
        if (obj is IDictionary<string, object> dict) {
            return dict.ContainsKey(name);
        }
        return obj.GetType().GetProperty(name) != null;
    }

This is working for me-:

  public static bool IsPropertyExist(dynamic dynamicObj, string property)
       {
           try
           {
               var value=dynamicObj[property].Value;
               return true;
           }
           catch (RuntimeBinderException)
           {

               return false;
           }

       }

Merging and fixing answers from Serj-TM and user3359453 so that it works with both ExpandoObject and DynamicJsonObject. This works for me.

public static bool HasPropertyExist(dynamic settings, string name)
{
    if (settings is System.Dynamic.ExpandoObject)
        return ((IDictionary<string, object>)settings).ContainsKey(name);

    if (settings is System.Web.Helpers.DynamicJsonObject)
    try
    {
        return settings[name] != null;
    }
    catch (KeyNotFoundException)
    {
        return false;
    }


    return settings.GetType().GetProperty(name) != null;
}

Using reflection, this is the function i use :

public static bool doesPropertyExist(dynamic obj, string property)
{
    return ((Type)obj.GetType()).GetProperties().Where(p => p.Name.Equals(property)).Any();
}

then..

if (doesPropertyExist(myDynamicObject, "myProperty")){
    // ...
}