Question

Okay, so a while ahead I posted how to read other config files of other programs (here is the link Previous Post. I managed to do it. But now there is another problem. The scenario is like this, I have two programs. Program A reads its configuration from a config file and program B is only used to modify the contents of the config file which A reads. The name of the config file is email.config. It is in the same directory in which program A & B resides.

The problem is that I get path of a file for attachment using open file dialog. If the path points to a file in the same directory, the program works perfect! But if it points to a file outside the directory it throws an exception of type System.NullReferenceException.

Here is the code

private void saveBtn_Click(object sender, EventArgs e)
{
    try
    {
        // save everything and close
        string attachment = attachTxtBox.Text;

        var configMap = new ExeConfigurationFileMap { ExeConfigFilename = configFileName };
        // it throws exception here when
        // the path points to a file outside the exes directory
        Configuration externalConfig = ConfigurationManager.OpenMappedExeConfiguration(configMap, ConfigurationUserLevel.None);

        externalConfig.AppSettings.Settings["ServerAddress"].Value = serverAddr;
        externalConfig.AppSettings.Settings["Port"].Value = port;
        externalConfig.AppSettings.Settings["SSL"].Value = ssl.ToString();
        externalConfig.AppSettings.Settings["Sender"].Value = senderAddr;
        externalConfig.AppSettings.Settings["SenderPassword"].Value = password;
        externalConfig.AppSettings.Settings["Subject"].Value = subject;
        externalConfig.AppSettings.Settings["AttachmentPath"].Value = attachment;
        externalConfig.AppSettings.Settings["Body"].Value = messageBody;

        // Save values in config
        externalConfig.Save(ConfigurationSaveMode.Full);
        Application.Exit();
    }
    catch (System.Exception ex)
    {
        MessageBox.Show("Error: " + ex.Message);
        Application.Exit();
    }
}

The content of email.config is:

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings file="">
    <clear />
    <add key="ServerAddress" value="" />
    <add key="Port" value="" />
    <add key="Sender" value="" />
    <add key="SenderPassword" value="" />
    <add key="Subject" value="" />
    <add key="AttachmentPath" value="" />
    <add key="Body" value="" />
  </appSettings>
</configuration>

What am I doing wrong here?

EDIT: The value of configFileName is “email.config”

Answer 1

Well, I figured it out myself after debugging for almost 5 hours, Damn!

The problem was when I used OpenFileDialog to get the file path, it changed the current directory to the one which is selected in the dialog, so the program couldn’t find the config file. All I did was to set the RestoreDirectory property of OpenFileDialog to true and poof it worked

Thanks everyone, ChrisF, Eoin Campbell and pablito.