c# - Removing the hard coded value to app.config file -

i have developed form takes user user id , password , display list of databases available in local server.now have done in hard coded format...like this

public void binddbdropdown() {     //create connection object     sqlconnection sconnection = new sqlconnection(         configurationsettings.appsettings["connectionstring"]);      //to open connection.     sconnection.open();      //query select list of databases.     string selectdatabasenames =         @"select name master..sysdatabases";      //create command object     sqlcommand scommand =          new sqlcommand(selectdatabasenames, sconnection);      try     {         //create data set          dataset sdataset = new dataset("master..sysdatabases");          //create dataadapter object         sqldataadapter sdataadapter =              new sqldataadapter(selectdatabasenames, sconnection);         sdataadapter.tablemappings.add("table",              "master..sysdatabases");          //fill dataset         sdataadapter.fill(sdataset);          //bind database names in combobox         dataviewmanager dsv = sdataset.defaultviewmanager;          //provides master mapping between sourcr table          //and system.data.datatable         cmbdatabases.datasource =              sdataset.tables["master..sysdatabases"];         cmbdatabases.displaymember = "name";         cmbdatabases.valuemember = ("name");     }     catch(exception ex)     {         //all exceptions handled , written in eventlog.         eventlog logexception = new eventlog("application");         logexception.source = "mfdbanalyser";         logexception.writeentry(ex.message);     }         {         //if connection not closed close connection         if(sconnection.state != connectionstate.closed)         {             sconnection.close();         }     } }  /// <summary> ///this function binds names of tables primary  ///keys in dropdown cmbresults. /// </summary> public void getprimarykeytable() {     //an instance of connection string created manage     //the contents of connection string.     var sqlconnection = new sqlconnectionstringbuilder();     sqlconnection.datasource = "192.168.10.3";     sqlconnection.userid = "gp";     sqlconnection.password = "gp";     sqlconnection.initialcatalog =          convert.tostring(cmbdatabases.selectedvalue);     string connectionstring = sqlconnection.connectionstring;      sqlconnection sconnection = new sqlconnection(connectionstring);      //to open connection.     sconnection.open();      //query select table_names have primary_keys.     string selectprimarykeys = @"         select  table_name             information_schema.table_constraints            constraint_type = 'primary key'         ,     table_name <> 'dtproperties'         order table_name";      //create command object     sqlcommand scommand =          new sqlcommand(selectprimarykeys, sconnection);      try     {         //create dataset         dataset dslistofprimarykeys =              new dataset("information_schema.table_constraints");          //create dataadapter object         sqldataadapter sdataadapter =              new sqldataadapter(selectprimarykeys, sconnection);          //provides master mapping between sourcr table          //and system.data.datatable         sdataadapter.tablemappings.add("table",              "information_schema.table_constraints");          //fill dataset         sdataadapter.fill(dslistofprimarykeys);          //bind result combobox primary key tables         dataviewmanager dvmlistofprimarykeys =              dslistofprimarykeys.defaultviewmanager;         dgresultview.datasource = dslistofprimarykeys             .tables["information_schema.table_constraints"];     }     catch(exception ex)     {         //all exceptions handled , written in eventlog.         eventlog log = new eventlog("application");         log.source = "mfdbanalyser";         log.writeentry(ex.message);     }         {         //if connection not closed close connection         if(sconnection.state != connectionstate.closed)         {             sconnection.dispose();         }     } } 

can me in removing these hardcoded things , taking local server address, userid , password app.config file directly???

sure.

first, open app.config or web.config file.

look following section

<appsettings>     <add key="...." value="....." />     .... </appsettings> 

if doesn't exist, should added.

now add following key/values...

<add key="myserver" value="192.168.10.3" /> <add key="myuserid" value="gp" /> <add key="mypassword" value="gp" /> 

and example of app.config can like...

<?xml version="1.0" encoding="utf-8" ?> <configuration>    <appsettings>         <add key="myserver" value="192.168.10.3" />       <add key="myuserid" value="gp" />       <add key="mypassword" value="gp" />    </appsettings> </configuration>  

kewl. lets update code. trick use configurationmanager.appsettings class :-

change...

sqlconnection.datasource = "192.168.10.3"; sqlconnection.userid = "gp"; sqlconnection.password = "gp"; 

to..

sqlconnection.datasource = configuationmanager.appsettings["myserver"]; sqlconnection.userid = configuationmanager.appsettings["myuserid"]; sqlconnection.password = configuationmanager.appsettings["mypassword"]; 

now can change values of key/values (in app.config or web.config) without having compile code :)

hth