Missing partial modifier on declaration of type 'xxx'; [Solved]

Make sure you have added partial  keyword  as prefix while defining more pertial class.
I was getting the error:
Missing partial modifier on declaration of type 'xxx'; another partial declaration of this type exists E:\...Cs xxx

Error 1 Missing partial modifier on declaration of type 'CisplVerifier.CisplDocument'; another partial declaration of this type exists E:\C# Examples\Signature Validation\Signature Verifier\Const.cs 10 12 CisplVerifier

My code was

partial class CisplDocument
{
    public int var1 = 1;
}

class CisplDocument // partial is missing
{
    public int var2 = 2;
}


Solution 

partial class CisplDocument
{
    public int var1 = 1;
}

partial class CisplDocument // partial added
{
    public int var2 = 2;
}