using methods of other forms

Question

Is it possible for one form to use a method that is declared in another form? One of the forms I have in an MDI has an oleDBAdapter on it and rather than create an adapter on the new form I'd like to just call a method in the previous form, pass it an array, and update the database from there. Is that possible? And if it is, how do you do it?

niklaskenez · Answer

I totally agree with Admin that you should use a separate class for the OLEDB connection data adapter and dataset (see my class in the end). You can put them all in a same class but the DBconnection in the constructor and when receiving data in a method call getData. Of course you can do it in other ways; put it all in the constructor or in two seperated methods. The answer on your question though is that you first have to instantiate the class where the method you want to use is located to greate an object (arguments are those variables you're sending to the constructor; if the're required). Classname objName = new Classname(arguments); Then you use the greated object to reach the public method in that class like this: objName.methodName(arguments); since you probably have a return value you write it like this (in C# members is normally the same as variables in this case it is but it can also be methods etc): membertype membername = objName.methodName(arguments); Here’s a complete example (see the DBconnect code in the end): The class name is: DBconnect The method name is: getData The object name is: objDBcon The member (variable) name is: ds The member type (normally string int etc.) is: DataSet The arguments are those members (variables) you’re sending to the method/class constructor. In this case you will send a SQL query or a Store Procedure: qSQL So this is what your code look like from another class that will reach the getData method in the DBconnect class: DBconnect objDBcon = new DBconnect(userName passWord); DataSet ds = objDBcon.getData(qSQL); As you see through the greated object you can reach the method in a class (as well as a form class) as long the method is public and you’re sending the required arguments to the method. Below you can see a class I made for my DB connection to a SQL server. The dbIniString needs to be written in a long row otherways the concatenation wont work. To make it work with Access you only change the dbIniString. public class DBconnect { //Instance members============================= string userName; string passWord; string dbIniString; private OleDbConnection con; private OleDbDataAdapter da; private DataSet ds; //================End Instance members========== //Constructor================================= public DBconnect(string userName string passWord) { dbIniString = @Provider=SQLOLEDB.1;User ID= + userName + ;Password =  + passWord + ;Packet Size=4096;Initial Catalog=Patient; con = new OleDbConnection(dbIniString); try { con.Open(); } catch(Exception mess) { MessageBox.Show(mess.ToString()); } } //=============End constr.=================== //Method getData============================== public DataSet getData(string qSQL)//Methode { da = new OleDbDataAdapter(qSQL con); ds = new DataSet(); da.Fill(dstempTabel); con.Close(); return ds; } //==================End getData============= } //End class Regards Nick :o) C# is a tricky key to play in on a piano!

gurjar_mumbai · Answer

The better way to do it is create a class and have all the shared members (among multiple forms) in this class. In that case your shared code is not form dependent and you can add modularity to your app.