Adding a connection string in a class library

Question

User-184840539 posted

I am looking to create a class library that contains classes I want to share across multiple web applications.  I am trying to read the data from an SQL server in the library class but I don't have access to the system configuration manager to read connection string.  How can I keep a dynamic connection string in my class library?  Can I reference the library and then read the connection string from web.config and pass it back to the library. 

I am thinking of having a base class where I define a function called ConnectionString such as

public string ConnectionString()

    {

       string str = "";      return str;

     }

 

So in the library class I would use the following code:

string qry;

qry = "SELECT * FROM [TABLE] WHERE ([ID] = " + ID + ");";

SqlConnection cn = new SqlConnection();

cn.ConnectionString = this.ConnectionString();

cn.Open();

 

 .  . . .

Is it possible to do this using the library class??

I am hoping there is a way to set the Connection String for the whole library in the Web App with a single function...

Thanks

 

 

 

 

Answer 1

User807886609 posted

Your class library should be able to access the ConfigurationManager.ConnectionStrings section of the web.config as long as it has a reference to System.Configuration namespace. There should be no need to hard-code any connection strings.

Answer 2

User-1910946339 posted

Something like this

public class MyLibraryClass {
   private string connectionString;

   public MyLibraryClass(string connectionString) {
      this.connectionString = connectionString;
   }

   public something SomeMethod(int param) {
        SqlConnection cn = new SqlConnection(connectionString);
        cn.Open();
        ...
   }
}

 When your web applications wants to use the library they pass the connection string to the constructor

MyLibraryClass lib = new MyLibraryClass(ConfigurationManager.ConnectionStrings["MyConnection"].ConnectionString;
somthing x = lib.SomeMethod95);
...

 

 

Answer 3

User-1171043462 posted

string qry;

qry = "SELECT * FROM [TABLE] WHERE ([ID] = " + ID + ");";

SqlConnection cn = new SqlConnection();

cn.ConnectionString = this.ConnectionString();

cn.Open();

Instead you should use parameters as this can lead to sql injection

refer here it might also contain what you need else reply back

http://www.aspsnippets.com/post/Parameterized-Queries-ADONet.aspx

Answer 4

User-319574463 posted

 If you look at the CommonParam project at http://www.CodePlex.Com/CommonParam, there is code to read a connection string from an XML file.

 

Answer 5

User-184840539 posted

Thanks, for everyone's help.

Answer 6

User-1630302068 posted

I am trying to read the data from an SQL server in the library class but I don't have access to the system configuration manager to read connection string. 

 

 

You need to add a reference to the System.Configuration assembly from the GAC.