How to create connection string dynamically

Here i am using viewstate to create connection string at run time.

 protected void btnSubmit_Click(object sender, EventArgs e)  
 {   
      ViewState["DataScorceName"] = datasource;  
      ViewState["Customer"] = txtCustomer.Text;  
 }  
 public void MyFunction()  
 {   
      string sqlConnectionString = "Persist Security Info=True;User ID=sa;Password=Sa;Initial Catalog=" + DBName + ";Data Source='" + ViewState["DataScorceName"] + "'";  
 }