访问自定义配置文件 (CS0122) 中的应用设置
本文关键字:应用 设置 CS0122 自定义 配置文件 访问 | 更新日期: 2023-09-27 18:36:26
我正在尝试从自定义配置文件访问配置项,但收到错误CS0122。
类:
using System;
using System.IO;
using System.Configuration;
using System.Windows.Forms;
public class SaveLoadSettings
{
private static string path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.CommonApplicationData), "XMLConverterForTelekomInvoice", "XMLConverterForTelekomInvoice.config");
}
写入设置的功能:(这运行良好)
private static void AddUpdateAppSettings(string key, string value)
{
try
{
var configFile = ConfigurationManager.OpenMappedExeConfiguration(new ExeConfigurationFileMap { ExeConfigFilename = path }, ConfigurationUserLevel.None);
var settings = configFile.AppSettings.Settings;
if (settings[key] == null)
{
settings.Add(key, value);
}
else
{
settings[key].Value = value;
}
configFile.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection(configFile.AppSettings.SectionInformation.Name);
}
catch (ConfigurationErrorsException)
{
MessageBox.Show("Error writing app settings");
}
}
读取设置的功能:(这会在应用程序设置[键]上生成CS0122)
private static string ReadSetting(string key)
{
try
{
Configuration MyAppConfig = ConfigurationManager.OpenMappedExeConfiguration(new ExeConfigurationFileMap { ExeConfigFilename = path }, ConfigurationUserLevel.None);
var appSettings = MyAppConfig.AppSettings;
string result = appSettings[key] ?? string.Empty;
return result;
}
catch (ConfigurationErrorsException)
{
MessageBox.Show("Error reading app settings");
return string.Empty;
}
}
XML文件:
<?xml version="1.0" encoding="utf-8"?>
<configuration>
<appSettings>
<add key="Setting1" value="25" />
<add key="Setting2" value="10" />
</appSettings>
</configuration>
我是编码新手,我无法弄清楚我的代码中有什么问题。也许有些人可以帮助我。问候卡米
我在更改某些代码时遇到的问题:
string result = appSettings.Settings[key] ?? string.Empty; // Generates CS0019 ?? Operator can't be used on KeyValueConfigurationElement
string result = appSettings.Settings[key].ToString() ?? string.Empty; // Throws "System.NullReferenceException" in Runtime
编译器抱怨这一行: string result = appSettings[key] ?? string.Empty;
,具体来说,appSettings[key]
由于其保护级别而无法访问。
若要从自定义 .config 文件中提取设置值,可以使用 appSettings 实例上的"设置"属性:
private static string ReadSetting(string key)
{
try
{
Configuration MyAppConfig = ConfigurationManager.OpenMappedExeConfiguration(new ExeConfigurationFileMap { ExeConfigFilename = path }, ConfigurationUserLevel.None);
var appSettings = MyAppConfig.AppSettings;
string result = appSettings.Settings[key].Value ?? string.Empty; // ** change here
return result;
}
catch (ConfigurationErrorsException)
{
MessageBox.Show("Error reading app settings");
return string.Empty;
}
}
编辑:修复代码(缺少.值)
这是我对这个问题的解决方案:
private static string ReadSettingString(string key)
{
try
{
Configuration MyAppConfig = ConfigurationManager.OpenMappedExeConfiguration(new ExeConfigurationFileMap { ExeConfigFilename = path }, ConfigurationUserLevel.None);
var appSettings = MyAppConfig.AppSettings;
string result = appSettings?.Settings?[key]?.Value ?? string.Empty;
return result;
}
catch (ConfigurationErrorsException)
{
MessageBox.Show("Error reading app settings");
return string.Empty;
}
}
感谢您的帮助 史蒂夫·黄