Interfaces & Protected Methods - C# Discussion Boards

Re: sql connection string c# by coding

30-Aug-05 2:34

Create a connection object for the connection type you use, like an OleDbConnection object.
Put the connection string in the call to the constructor.
Create a command object for the connection type, like an OleDbCommand object.
Set the CommandText and CommandType properties.
Add parameter objects to the command object for any parameters you use in the query.
Open the connection.
Run the query using the method in the command object that fits what you want to do.
Dispose of the command object.
Dispose of the connection object. (This will automatically close the connection.)

---
b { font-weight: normal; }

jan larsen30-Aug-05 2:41

jan larsen

30-Aug-05 2:41

Like this:

public void Foo(string connectionString)
{
   using (SqlConnection connection = new SqlConnection(connectionString) )
   {
      // This is where to write whatever code you will be using your connection for.
      // The connection will be closed and disposed when leaving the 'using' block, whether
      // through normal execution or by a thrown exception.
   }
}

"God doesn't play dice" - Albert Einstein

"God not only plays dice, He sometimes throws the dices where they cannot be seen" - Niels Bohr

Re: sql connection string c# by coding

bozoo30-Aug-05 20:34

bozoo

30-Aug-05 20:34

dear All,

Thanks for your quick replay,

My application designed to be distributed app. on a network & 30 users & sql server DB & C#.net I put the DB on the (server Pc.
this is the first time using C# tool so,please advice which kind of provider sugest to use SQl, Oledb, Odbc,...) which make the connection and the perfomance is very smothly on the network.

Thanks for this kindly help

Wael Elassa

Application versioning

rmedo30-Aug-05 1:58

rmedo

30-Aug-05 1:58

we have a very huge distributed system and we make a lot of updates, a lot of bugs fixing and a lot of adding new features so I want to know if there is a versioning method rather than Assembly version to keep track with the system versions (major, minor, SPs) for every change and every update we made
Please any one know or have any paper talking about this subject, please inform me asap

Interfaces & Protected Methods

phimix30-Aug-05 1:19

30-Aug-05 1:19

Aloha,

We would like to make some nice controls based on the classic ASP.NET webcontrols. In order to secure that this is done probably, we would like to define an interface which defines the following:

    interface IControl<br />
    {<br />
        void OnInit(EventArgs e);<br />
<br />
        void Render(HtmlTextWriter output);<br />
<br />
        string HeaderText<br />
        {<br />
            get;<br />
            set;<br />
        }<br />
    }

The interface definitions of OnInit() and Render() are supposed to remind the coder that he should override the methods in the ASP.NET webcontrol. The problem is that these methods are protected and we therefore get the following error:

'MyButton' does not implement interface member 'IControl.OnInit(System.EventArgs)'. 'MyButton.OnInit(System.EventArgs)' is either static, not public, or has the wrong return type.

The HeaderText property works perfectly, but that is because it is implemented as public in the MyButton class.

Any ideas? If possible, we would love to be able to define protected methods in our interface... and if not possible, we would love to hear about another way of forcing the coders to implement everything.

Thanks, Mads

leppie30-Aug-05 1:35

leppie

30-Aug-05 1:35

Mads Phikamphon wrote:
methods are protected

make them public

Mads Phikamphon wrote:
define protected methods in our interface

no, but you can have private explicit interface implemantions.

Mads Phikamphon wrote:
we would love to hear about another way of forcing the coders to implement everything.

protected abstract

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

phimix30-Aug-05 2:42

30-Aug-05 2:42

Thanks for your reply.

We can't make the methods public since their are defined as protected in the ASP.NET controls that we inherit from (no change of access allowed when overriding base methods).

Also, we cannot use protected abstract since C# doesn't allow multiple inheritance (we already inherit from the control we want to extend).

"private explicit interface implementations" doesn't allow us to change access to a method, it still have to be the same as for the base class - so this is also a no go Frown | :(

// Mads

leppie30-Aug-05 2:51

leppie

30-Aug-05 2:51

Mads Phikamphon wrote:
Also, we cannot use protected abstract since C# doesn't allow multiple inheritance (we already inherit from the control we want to extend).

well extend the extended control! :p

^{xacc-ide 0.0.15 now with C#, MSIL, C, XML, ASP.NET, Nemerle, MyXaml and HLSL coloring - Screenshots}

Guffa30-Aug-05 3:10

30-Aug-05 3:10

Override the methods with a method that throws an (informative) exception. That way the coder have to override also.

---
b { font-weight: normal; }

phimix30-Aug-05 3:34

30-Aug-05 3:34

How would you do that? When don't have a "middle" class where we can do the overriding.

Each of our control classes derive directly from a webcontrol - I think adding a class between the webcontrol and our class would be the same as doing most of the work ourselves Frown | :(

Guffa31-Aug-05 21:04

31-Aug-05 21:04

Then you can't do it. You cannot change the behaviour of a class using interfaces, you can only specify behaviour to be added. To change the behaviour of a class you need to inherit it.

---
b { font-weight: normal; }

phimix1-Sep-05 0:27

1-Sep-05 0:27

We don't want to change the behaviour - we just want to make sure that some protected methods are overriden in the classes that inehrit from the base class.

Thanks for your help.

Guffa1-Sep-05 5:50