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Adding a Country List combo box/Dropdown list in ASP.NET

In webforms that involve address or contact details entry, we commonly put a Combobox / dropdown list of countries which the users choose from. And in the backend, we store a two-letter or three-letter ISO standard country code instead of storing the full name of the country. This is to keep with standards, and to eliminate storing constants like country name in every record which eventually might not be considered good implementation.

In this article, we will implement such a DropDownList box for an ASP.NET page.
Though C# is used as coding language, the steps are same for any other programming language.

STEP 1: Download / create a CSV country list to use.

This could be the difficult part especially with many different possible country lists on the Net.

But, Andrew Patton makes it easy for us, for he has researched different sources and compiled a list of countries with country code, country's official currency, the TLD subdomain allotted for the country etc., I should say Andrew Patton's list is very comprehensive, and he further posts on his website an XML and a CSV version of the list. You could download the CSV / XML versions from here.

Below code uses a reduced CSV list of countries from Andrew Patton's list.. for I have removed the disputed territories/countries from the list, and also shortened the names of a few countries to keep the width of the final DropDownList within optimal size. You can download my copy of the CSV list from the top of this article.

STEP 2: Get a connection string and set its properties

We will use ADO.NET to open the CSV file as a Table and read data.. this helps do a sql query to extract data.. What not, later you could do a join on this and other text or CSV files with normal sql queries.

The connection string we will use is: (source: connectionStrings.com)

Provider=Microsoft.Jet.OLEDB.4.0;
Data Source=c:txtFilesFolder;
Extended Properties="text;
HDR=Yes;FMT=Delimited";

[countrylist.csv]
Format=CSVDelimited
ColNameHeader=True
MaxScanRows=0
CharacterSet=ANSI

STEP 3: Extract the data from the file

(Explanation below code)

public static DataSet getCountryList()
{
    DataSet tmpDS = new DataSet();
    OleDbConnection tmpCon = null;
    try
    {
        tmpCon = new OleDbConnection(
"Provider=Microsoft.Jet.OLEDB.4.0;
Data Source="+
"c:temptxtFiles;"+
"Extended Properties="text;
HDR=Yes;FMT=Delimited";");

        tmpCon.Open();
        OleDbDataAdapter tmpDA = 
          new OleDbDataAdapter("
          select * from countrylist.csv",
          tmpCon);
        tmpDA.Fill(tmpDS);
    }
    catch(Exception ex)
    {}
    finally
    {
        tmpCon.Close();
        tmpCon=null;
    }
    return tmpDS;
}

All that we do to implement the read operation is:

1. Open the folder as a ADO.NET oleDBconnection (remember to import the System.Data.OleDb namespace at the top of your code like "using System.Data.OleDb;")

2. Perform a query on the file we are interested in, and extract the data to a DataSet.

The code above is a standard operation for extracting any database query result to a DataSet. Nothing new as you see. So this implementation could be used for working with both comma or tab delimited text files, and do joins on the files, all without the use of any database engine.

As you can see, we are done implementing the extraction part.. We now, only have to bind the country data to a Combobox or in to a ASP.NET DropDownList control.

STEP 4: Bind the data to an ASP.NET DropDownList control

The sample source to do this binding is as below.
ddlCountryList is the ID of the DropDownList control on my ASP.NET page.

private void loadCountryList()
{
    DataSet tmpDS = Data.getCountryList();
    if (tmpDS.Tables.Count == 1)
    {
        DataView tmpVw = 
           tmpDS.Tables[0].DefaultView;
        tmpVw.Sort = "Common Name";
        
        ddlCountryList.DataSource =
            tmpVw;
        ddlCountryList.DataTextField =
            "Common Name";
        ddlCountryList.DataValueField = 
            "ISO 3166-1 2 Letter Code";
        ddlCountryList.DataBind();
    }
}

We are done.. Test the code..

References:

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