app.Config中的ConnectionString不起作用

Question

In my winform project I have a connection string to connect to SQL. I have this connection in app.config file like this;

 <connectionStrings>
  <add name="MyConnectionString" providerName="System.Data.SqlClient"
        connectionString="Server=(localdb)\\v11.0; Integrated Security=true; AttachDbFileName=C:\\Folder\\mydataBaseName.mdf;Connect Timeout=15;Encrypt=False;TrustServerCertificate=False" 
   />

and I get the connection:

string config = ConfigurationManager.ConnectionStrings["MyConnectionString"].ConnectionString;
//and then
 using (SqlConnection conexao = new SqlConnection(config))
        {
            conexao.Open();
         .......
         .......
        }

When I run the app I get an error saying : "An unhandled exception of type 'System.Data.SqlClient.SqlException' occurred in System.Data.dll"

But If I call the connection string directlly from code (not using the app.config) everthing is ok .

string config = "Server=(localdb)\\v11.0; Integrated Security=true; AttachDbFileName=C:\\Folder\\mydataBaseName.mdf;Connect Timeout=15;Encrypt=False;TrustServerCertificate=False";

Any ideias, how to solve the problem ?

Thanks Leonor

Answer 1

In a C# non-verbatim string literal, \\\\ is used if you want to include a single backslash character in a string.

In other files, backslash is not necessarily a special character. In Web.config connection strings, you can include the backslash directly, without doubling it.

Or, in other words, the reason one connection string works and the other doesn't, is because you've really got two different connection strings.