c# - Custom "At least" attribute -

i'm trying create attribute validate model.

in model have list. list must have determined number of items matches criteria, "at least 1 active item" or "at least 1 active item "john" name".

my code this:

public class foo {     [atleast(1, new tuple<string, object>("active", true))]     public list<item> listofsomething { get; set; }      [atleast(1, new tuple<string, object>("active", true), new tuple<string, object>("name", "john"))]     public list<item> anotherlist { get; set; } }  public class item {     public string name { get; set; }     public bool active { get; set; } } public class atleastattribute : validationattribute {     public int minlength { get; set; }     public tuple<string, object>[] propertiesandvalues { get; set; }       public atleastattribute(int minlength,params tuple<string, object>[] propsnvalues)     {         minlength = minlength;         propertiesandvalues = propsnvalues;     } } 

i trying pass tuple<string, object> property , wanted value. i'm getting error:

an attribute argument must constant expression, typeof expression or array creation expression of attribute parameter type

anyone has way this?

agreeing comment davidg; way supply kind of constant-create expressions limiting primitive types. if want implement constraint values specify should convertible string.

then can think of syntax like

name=john;active=true 

but it's not simple, might want include ; or = in string values, need figure out string syntax , escape character:

name='john\\'s pizza' 

or

name='john''s pizza' 

then need parse information; regex might able it.

if can without string values containing characters use splitting, split string on ; = , presto.