Many times, you may need to get the list of currently set up ODBC data source names on the machine where your code is running from. There is no .NET API to get this list so you have to monkey with Windows registry a bit to find the list. There are 2 different types of ODBC data sources you can set up (User and System). The Data Source Names can be found in Windows by going to Administrative Tools->Data Sources(ODBC). The dialog looks like this: To get this list of data source names programmatically, I've created a simple class that you can use to get all System DSN's, User DSN's, or all DSN's. The list is returned already sorted so that it can be put directly into a drop down list easily and displayed to the user as needed. Getting System DSN's Here is the method that returns System DSN's:

/// <summary>
/// Gets all System data source names for the local machine.
/// </summary>
public System.Collections.SortedList GetSystemDataSourceNames()
{
    System.Collections.SortedList dsnList = new System.Collections.SortedList();

    // get system dsn's
    Microsoft.Win32.RegistryKey reg = (Microsoft.Win32.Registry.LocalMachine).OpenSubKey("Software");
    if (reg != null)
    {
        reg = reg.OpenSubKey("ODBC");
        if (reg != null)
        {
            reg = reg.OpenSubKey("ODBC.INI");
            if (reg != null)
            {
                reg = reg.OpenSubKey("ODBC Data Sources");
                if (reg != null)
                {
                    // Get all DSN entries defined in DSN_LOC_IN_REGISTRY.
                    foreach (string sName in reg.GetValueNames())
                    {
                        dsnList.Add(sName, DataSourceType.System);
                    }
                }
                try
                {
                    reg.Close();
                }
                catch { /* ignore this exception if we couldn't close */ }
            }
        }
    }

    return dsnList;
}

Getting User DSN's Here is the method that returns User DSN's:

/// <summary>
/// Gets all User data source names for the local machine.
/// </summary>
public System.Collections.SortedList GetUserDataSourceNames()
{
    System.Collections.SortedList dsnList = new System.Collections.SortedList();

    // get user dsn's
    Microsoft.Win32.RegistryKey reg = (Microsoft.Win32.Registry.CurrentUser).OpenSubKey("Software");
    if (reg != null)
    {
        reg = reg.OpenSubKey("ODBC");
        if (reg != null)
        {
            reg = reg.OpenSubKey("ODBC.INI");
            if (reg != null)
            {
                reg = reg.OpenSubKey("ODBC Data Sources");
                if (reg != null)
                {
                    // Get all DSN entries defined in DSN_LOC_IN_REGISTRY.
                    foreach (string sName in reg.GetValueNames())
                    {
                        dsnList.Add(sName, DataSourceType.User);
                    }
                }
                try
                {
                    reg.Close();
                }
                catch { /* ignore this exception if we couldn't close */ }
            }
        }
    }

    return dsnList;
}

Getting all DSN's Now we can call the 2 previous methods and combine their results to get a full list of DSN's:

// Returns a list of data source names from the local machine.
public System.Collections.SortedList GetAllDataSourceNames()
{
    // Get the list of user DSN's first.
    System.Collections.SortedList dsnList = GetUserDataSourceNames();

    // Get list of System DSN's and add them to the first list.
    System.Collections.SortedList systemDsnList = GetSystemDataSourceNames();
    for (int i = 0; i < systemDsnList.Count; i++)
    {
        string sName = systemDsnList.GetKey(i) as string;
        DataSourceType type = (DataSourceType)systemDsnList.GetByIndex(i);
        try
        {
            // This dsn to the master list
            dsnList.Add(sName, type);
        }
        catch 
        { 
            // An exception can be thrown if the key being added is a duplicate so 
            // we just catch it here and have to ignore it.
        }
    }

    return dsnList;
}

To use these methods, you can bind them to a Combo Box with code similar to this:

// fill data source names
DevToolShed.OdbcDataSourceManager dsnManager = new DevToolShed.OdbcDataSourceManager();
System.Collections.SortedList dsnList = dsnManager.GetAllDataSourceNames();
for (int i = 0; i < dsnList.Count; i++)
{
    string sName = (string)dsnList.GetKey(i);
    DevToolShed.DataSourceType type = (DevToolShed.DataSourceType)dsnList.GetByIndex(i);
    cbxDataSourceName.Items.Add(sName + " - (" + type.ToString() + " DSN)");
}

The entire class for OdbcDataSourceManager can be downloaded here: OdbcDataSourceManager.zip