c# application checkbox to connect to different databases

How are you connecting to the database? Via Entity Framework, or dbcontext, or custom SQLConnection classes?

One thing you can do , as soon as user selects a checkbox, get the value of connection string and server Ip from web.config as

ConnectionStringSettings conSettings = ConfigurationManager.ConnectionStrings[VARIABLENAME];

and the app setting.

Replace the ** by app setting value and pass the connectionstring to the database connection class.

You can use formatted variables like shown below:

string connectionString = String.Format("Data Source={0};Initial Catalog=" + Master + ";Persist Security Info=True;Connect Timeout=0;User ID=" + ConfigurationSettings.AppSettings["username"] + ";Password=" + ConfigurationSettings.AppSettings["password"], <get value from checkbox>);

Each checkBox has a checkBox.Checked parameter, so you can make a function that will insert the proper IP address when a checkBox is checked:

if(checkBox1.Checked) { string DataSource = some IP address; }

and you repeat this code for each pair of checkBox/IP address you have.

P.S since you probably want to connect to only one database in one moment, you should use radioButtons instead of checkBoxes

i don't know why you use CheckBox. if you need yo be connected to only one DB you should use RadioBox. if anyway you need several DB you can registed the checkBox Checked event:

     this.checkBox1.CheckedChanged += new System.EventHandler(this.checkBox1_CheckedChanged);

and do:

  private void checkBox1_CheckedChanged(object sender, EventArgs e)
  {
     if (checkBox1.Checked)
     {
        string currStr = ConnectionString.Replace("*****", currIP);// the currIP is up to u  
     }
     else
     {

     }

  }

now you can put them all in a list

List<string> connStrings = new List<string>();

and do

  private void checkBox1_CheckedChanged(object sender, EventArgs e)
  {
     string currStr = ConnectionString.Replace("*****", currIP);// the currIP is up to u  

     if (checkBox1.Checked)
     {
        connStrings.Add(currStr);
     }
     else
     {
        connStrings.Remove(currStr);
     }

  }

now that you got them all in a list you can use it with a foreach

foreach(string curr in connStrings)
{
}

i do remind that you'll have to register each CheckBox to his own event method

I had a scenario where i had to use 5 different databases in one application.

What is did is, i had a single class DBUtility which provides all database related functionality. in this class i had a method called init() which initializes my connection string.

so i created other 4 classes which inherited from the main class DBUtility and override the init() method to different connection strings.

You can also create similar structure and then based on checkbox selection create object of required class

e.g.

DBUtility obj = new DBUtility2();

where

public class DBUtility
{
public SqlConnection cn;
 public void init()
{
//initialize cn here
}

public DataSet getdata(string query)
{
//execute query using cn
}
}

public class DBUtility2 : DBUtility
{
public void init()
{
//initialize cn here
}
}