How to reference a control in Asp.Net C# for a textbox, dropdownlist, etc

Question

How to reference a control? Using a DropDownList as an example. I want to reference "ddlName" (name of existing dropdownlist) just like using macro in VFP. I eventually want to use this to pass parameter. Thank You in advance!

protected void PopulateName() {  
        string DataPara= "name";         // Parameter1    
        SqlPara = "SELECT x FROM x";     // Parameter2     
        newname = "ddlName";             // Parameter3      ?          
        SqlConnection connData = new SqlConnection();
        connData.ConnectionString = 
            ConfigurationManager.ConnectionStrings["ConnSqlUsr"].ConnectionString;
        connData.Open();            
        SqlCommand connCmd = new SqlCommand(SqlPara, connData);     
        SqlDataReader connDr = connCmd.ExecuteReader();     
        newname.DataSource = connDr;       ?    
        newname.DataValueField = DataPara; ?        
        newname.DataTextField = DataPara;  ?            
        newname.DataBind();                ?       
        connDr.Close();           
        connDr.Dispose();         
        connCmd.Dispose(); 

Answer 1

LoginView1 is page name

     DropDownList ddl =  (DropDownList)LoginView1.FindControl("ddlName");
 ddl.DataSource = connDr;       ?    
        ddl.DataValueField = DataPara; ?        
        ddl.DataTextField = DataPara;  ?            
        ddl.DataBind();