Windows 服务未从 App.config 获取值

我创建了简单的Windows服务，如下所示：

   private void TraceService(string content)
        {
            try
            {
                string path = ConfigurationManager.AppSettings["TextLocation"];
                FileStream fs = new FileStream(@path, FileMode.OpenOrCreate, FileAccess.Write);
                StreamWriter sw = new StreamWriter(fs);             
                sw.BaseStream.Seek(0, SeekOrigin.End);                
                sw.WriteLine(content);         
                sw.Flush();             
                sw.Close();
            }
            catch (Exception ex)
            {
                FileStream fs = new FileStream(@"D:'Error.txt", FileMode.OpenOrCreate, FileAccess.Write);            
                StreamWriter sw = new StreamWriter(fs);              
                sw.BaseStream.Seek(0, SeekOrigin.End);               
                sw.WriteLine(ex.Message);
                sw.Flush();               
                sw.Close();
            }
        }

如果我使用 Installutil 在 VS 命令提示符下运行此服务，那么它会从 app.config 获取值。 但我需要使用 WixInstaller 创建安装程序。 当我运行安装程序并启动服务时，它会抛出异常和消息，另存为"路径不能为空"。这是什么原因呢？我该如何解决这个问题？

编辑：我的应用程序配置如下：

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key="TextLocation" value="d:'ScheduledServiceNew.txt"/>
  </appSettings>
</configuration>

我的 Wix 安装程序文件 ：

<?xml version="1.0" encoding="utf-8"?>
<Wix xmlns="http://schemas.microsoft.com/wix/2006/wi" xmlns:util="http://schemas.microsoft.com/wix/UtilExtension">
    <Product Id="5AC767F2-4F21-45DF-9DAB-C013C62B2B67" Name="Installer" Language="1033" Version="1.0.0.0" Manufacturer="TRT " UpgradeCode="3fd83540-23f6-45f4-bb1c-e77c12725680">
        <Package InstallerVersion="200" Compressed="yes" />
        <Media Id="1" Cabinet="SampleApp.cab" EmbedCab="yes" />
        <Directory Id="TARGETDIR" Name="SourceDir">
            <Directory Id="ProgramFilesFolder">
                <Directory Id="INSTALLFOLDER" Name="Installer">
                    <Directory Id="TestService" Name="TestService">
                        <Component Id="MainExecutable" Guid="CE30D5D8-3211-4890-A9DC-0C315C15B39E">
                            <File Id="testServiceexe" Name="TestInstallerProject.exe" DiskId="1" KeyPath="yes" Source="..'TestInstallerProject'bin'Debug'TestInstallerProject.exe" />
                            <File Id="App.config" Name="App.config" Source="..'TestInstallerProject'App.config" />
                            <ServiceInstall Name="ScheduledService" Type="ownProcess" Start="auto" ErrorControl="ignore" Id="ServiceInstaller" DisplayName="ScheduledService" Account="[SERVICEACCOUNT]" Password="[SERVICEACCOUNTPASSWORD]">
                                <util:ServiceConfig FirstFailureActionType="restart" SecondFailureActionType="restart" ThirdFailureActionType="restart" ResetPeriodInDays="1" RestartServiceDelayInSeconds="1" />
                            </ServiceInstall>
                            <ServiceControl Id="StartService" Name="ScheduledService" Start="install" Stop="both" Remove="uninstall" Wait="no" />
                            <RemoveFolder Id="INSTALLDIR" On="uninstall" />
                        </Component>
                    </Directory>
                </Directory>
            </Directory>
        </Directory>
        <Feature Id="Complete" Title="Installer" Level="1">
            <ComponentRef Id="MainExecutable" />
        </Feature>
        <UI />
    </Product>
</Wix>