Using Character Encoding in ASP.NET

• Download demo project - 45 Kb

Introduction

This sample shows how to put your text completely into the operation system or database which does not support the text's character set.

Background

In web application development, frequently I have to connect each kind of old database and OS from customers such as SCO5.05 which does not support UTF-8, GB2312 and other character sets. So, how to completely store or take out my text data has became an important job.

Once on a project, I needed to put some Chinese words in UTF-8 into the system of SCO5.05 + Informix7.3. But when I check the database, found that all characters were changed into "->" (\0x7F) in fact. Many ways I tried, but ever could not solve this problem.

Why?

I found the answer later: this is the trouble of character encoding.

Open the file named web.config in the ASP.NET project. The value of requestEncoding attribute in globalization element is "utf-8". It means the requested texts were encoded as UTF-8 character set. Because SCO5.05 does not support UTF-8, therefore the requested texts where changed.

I got it. The texts should be encoded into the western language (iso8859-1) which SCO5.05 can distinguish from UTF-8 before saving, and converted back after loading.

Solution code

For example, to put the message "ÄãºÃPi(\u03a0)", means "Hello Pi(¦°)", into "memo" field of database, use the following code:

// message "Hello pi(¦°)" in Chinese
string unicodeStr = "ÄãºÃPi(\u03a0)";

OdbcConnection conn = new OdbcConnection();
System.Data.IDbCommand cmd = conn.CreateCommand();

conn.ConnectionString = "your connection string";
cmd.Connection = conn;

// Encoding here
cmd.CommandText = "INSERT INTO encoding VALUES ('" 
  + CEncoding.unicode_iso8859(unicodeStr) + "')";
cmd.Connection = conn;
conn.Open();
cmd.ExecuteNonQuery();
conn.Close();

I used the function unicode_iso8859() above. It can convert the texts from UTF-8 to ISO8859-1.

public static string unicode_iso8859(string src) {
  Encoding iso = Encoding.GetEncoding("iso8859-1");
  Encoding unicode = Encoding.UTF8;
  byte[] unicodeBytes = unicode.GetBytes(src);
  return iso.GetString(unicodeBytes);
}

public static string iso8859_unicode(string src) {
  Encoding iso = Encoding.GetEncoding("iso8859-1");
  Encoding unicode = Encoding.UTF8;
  byte[] isoBytes = iso.GetBytes(src);
  return unicode.GetString(isoBytes);
}

Select your database and take a look. Is that all the texts converted into ISO symbol which you do not recognized?

Then you can convert back reversely by using iso8859_unicode() function. Of course, you can convert back with other encodings as you want.

If you are using an adapter and binding a DataSet to a DataGrid, it is easy to encode the data with these two methods, too. But you will pay the cost of more time. Use it or not? It is under your own judgment. J

OdbcAdapter adapter = new OdbcAdapter(); 
DataSet1 ds = new DataSet1(); 
DataGrid grid = new DataGrid(); 
OdbcConnection conn = new OdbcConnection(); 

// conn, adapter, dataset and datagrid were initialized 
conn.ConnectionString = "your connection string"; 
adapter.Connection = conn;
adapter.Fill(ds);

string xml = ds.GetXml();
ds.Clear();

// encoding here
ds.ReadXml(new System.IO.StringReader(CEncoding.iso8859_unicode(xml)));
grid.DataBind();

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here