c# - Why can I not assign the concatenation of constant strings to a constant string? -

occasionally want break apart constant string formatting reasons, sql.

const string select_sql = "select field1, field2, field3 table1 field4 = ?"; 

to

const string select_sql = "select field1, field2, field3 "                          + "from table1 "                          + "where field4 = ?"; 

however c# compiler not allow second form constant string. why?

um, should fine... sure doesn't compile?

sample code:

using system;  class test {     const string myconstant = "foo" + "bar" + "baz";      static void main()     {         console.writeline(myconstant);     } } 

my guess in real code you're including non-constant expression in concatenation.

for example, fine:

const string myfield = "field"; const string sql = "select " + myfield + " table"; 

but isn't:

static readonly string myfield = "field"; const string sql = "select " + myfield + " table"; 

this attempting use non-constant expression (myfield) within constant expression declaration - , that's not permitted.