Runtime casting of an object type to access it's properties (C#)

Question

How can I cast an object type at runtime?

Suppose I have a method GetProperties() that has one parameter of type object. I pass either a parameter (of type ParameterInfo) or a property (of type PropertyInfo) to this method. I want to get the name of the passed parameter/property. In the below code, I am able to get the type of the object passed. Now I am stuck on how to type cast the object to get the name of the parameter?  

public void GetProperties(object obj)
{
  Type t = obj.GetType();
  string name = ((t)obj).Name;
}

 

 

 

Answer 1

If you know those are the only two types being passed, I'd recommend overloading the method:

public void GetProperties(ParameterInfo parameter)
{
 string name = parameter.Name;
  // Use name...
}

public void GetProperties(PropertyInfo propertyInfo)
{
  string name = propertyInfo.Name;
  // Use Name...
}

If you must leave a single method using object, you can do:

 

public void GetProperties(object obj)
{
 string name = string.Empty; 

 PropertyInfo propInfo = obj as PropertyInfo
 ParameterInfo paramInfo = obj as ParameterInfo;

 if (propInfo != null)
   name = propInfo.Name;
 else if (paramInfo != null)
   name = paramInfo.Name;
 else
   throw new ArgumentException("This method only accepts PropertyInfo and ParameterInfo arguments");
 
  // Use name...
}
 

---

Reed Copsey, Jr. - http://reedcopsey.com
If a post answers your question, please click "Mark As Answer" on that post and "Mark as Helpful".

Answer 2

Thanks Reed for your response. I am trying to make one generic method that can handle property and parameter both. I was planning to pass a parameter of type ParameterInfo and within call the function recursively for the properties for the passed parameter. That was the reason why I want to have a code that will work for any type (parameter/property). If I go with the second approach that you mentioned, then I need to have the logic repeated for both property and parameter types. Is it?

Also, can you tell me how can I get the name of the class if the passed value is an object of ClassA? In obj, I have the elements/properties of ClassA and that can be accessed using

foreach (PropertyInfo prop in obj.GetType().GetProperties())

But I don't know how to access class level information.. like Class Name should give me ClassA?

Answer 3

You can use obj.GetType() to get the System.Type for the object. Given the Type, you can use Type.Name (or Type.FullName) to retrieve the type's name:

 

    string objectTypeName = obj.GetType().Name;

 

---

Reed Copsey, Jr. - http://reedcopsey.com
If a post answers your question, please click "Mark As Answer" on that post and "Mark as Helpful".