Check if a property exists in a class

Question

I try to know if a property exist in a class  I tried this    public static bool HasProperty this object obj  string propertyName        return obj GetType   GetProperty propertyName     null      I don t understand why the first test method does not pass     TestMethod  public void Test HasProperty True         var res   typeof MyClass  HasProperty  Label        Assert IsTrue res       TestMethod  public void Test HasProperty False         var res   typeof MyClass  HasProperty  Lab        Assert IsFalse res

User · Answer

If you are binding like I was    lt    Container DataItem GetType   GetProperty  Property1      null   DataBinder Eval Container DataItem   Property1     DataBinder Eval Container DataItem   Property2      gt

User · Answer

This answers a different question   If trying to figure out if an OBJECT  not class  has a property    OBJECT GetType   GetProperty  PROPERTY      null   returns true if  but not only if  the property exists   In my case  I was in an ASP NET MVC Partial View and wanted to render something if either the property did not exist  or the property  boolean  was true    if   Model GetType   GetProperty  AddTimeoffBlackouts      null             Model AddTimeoffBlackouts    helped me here   Edit  Nowadays  it s probably smart to use the nameof operator instead of the stringified property name

User · Answer

I m unsure of the context on why this was needed  so this may not return enough information for you but this is what I was able to do   if typeof ModelName  GetProperty  Name of Property      null      whatevver you were wanting to do      In my case I m running through properties from a form submission and also have default values to use if the entry is left blank - so I needed to know if the there was a value to use - I prefixed all my default values in the model with Default so all I needed to do is check if there was a property that started with that

User · Answer

There are 2 possibilities   You really don t have Label property   You need to call appropriate GetProperty overload and pass the correct binding flags  e g  BindingFlags Public   BindingFlags Instance  If your property is not public  you will need to use BindingFlags NonPublic or some other combination of flags which fits your use case  Read the referenced API docs to find the details   EDIT   ooops  just noticed you call GetProperty on typeof MyClass   typeof MyClass  is Type which for sure has no Label property

User · Answer

I got this error   Type does not contain a definition for GetProperty  when tying the accepted answer   This is what i ended up with   using System Reflection   if  productModel GetType   GetTypeInfo   GetDeclaredProperty propertyName     null

User · Answer

Your method looks like this   public static bool HasProperty this object obj  string propertyName        return obj GetType   GetProperty propertyName     null      This adds an extension onto object - the base class of everything  When you call this extension you re passing it a Type   var res   typeof MyClass  HasProperty  Label      Your method expects an instance of a class  not a Type  Otherwise you re essentially doing  typeof MyClass  - this gives an instanceof  System Type      Then  type GetType   - this gives  System Type  Getproperty  xxx   - whatever you provide as xxx is unlikely to be on  System Type    As  PeterRitchie correctly points out  at this point your code is looking for property Label on System Type  That property does not exist   The solution is either  a  Provide an instance of MyClass to the extension   var myInstance   new MyClass   myInstance HasProperty  Label     b  Put the extension on System Type  public static bool HasProperty this Type obj  string propertyName        return obj GetProperty propertyName     null      and  typeof MyClass  HasProperty  Label

[c#] Check if a property exists in a class

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