如何在C＃中比较两个连接字符串

Question

I have a default connectionstring and a Connectionstring in the webconfig, like this:

<add name="BAG_Zipcodes" connectionString="Password=;Persist Security Info=True;
     User ID=sa;Initial Catalog=e;Data Source=" />

But if that connectionstring is not in webconfig. use this one:

ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

So I compare it like this:

var zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];
            //zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

if (zipcodeConnection == ConfigurationManager.ConnectionStrings["BAG_Zipcodes"] && zipcodeConnection != null)
    zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];

else if (zipcodeConnection == ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName] && zipcodeConnection != null) 
    zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

But If I delete this connectionstring from webconfig: add name="BAG_Zipcodes

then the connectionstring is always null.

Thank you

Answer 1

This can be done by using a coalesce statement.

var zipcodeConnection = (ConfigurationManager.ConnectionStrings["BAG_Zipcodes"])
                      ?? ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];

Answer 2

Oke, I solved like this:

var zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];


if (zipcodeConnection == ConfigurationManager.ConnectionStrings["BAG_Zipcodes"] && zipcodeConnection != null)
    zipcodeConnection = ConfigurationManager.ConnectionStrings["BAG_Zipcodes"];

else if (zipcodeConnection == null) 
    zipcodeConnection = ConfigurationManager.ConnectionStrings[DbSchema.DefaultConnectionName];