C 对App.config文件读取及写入方法

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在 C# 项目里，常常会把部分常用的参数值写入到 App.config 文件之中。当程序启动并开始运行时，会率先读取上一次写入的数值。

本文将以模拟量对应通道的设置值以及最大值为例，来实现对应内容的读取与写入操作。

1. 双击打开App.config文件

在<appSettings> 与</appSettings >之间添加需要读写的参数值（注意：需要以键值对的方式，如下文所示）。

<?xml version=“1.0“ encoding=“utf-8“?>

<configuration>

<configSections>

<!– For more information on Entity Framework configuration, visit http://go.microsoft.com/fwlink/?LinkID= –>

<section name=“entityFramework“ type=“System.Data.Entity.Internal.ConfigFile.EntityFrameworkSection, EntityFramework, Version=6.0.0.0, Culture=neutral, PublicKeyToken=b77a5ce089“ requirePermission=“false“ />

</configSections>

<startup>

<supportedRuntime version=“v4.0“ sku=“.NETFramework,Version=v4.7.2“ />

</startup>

<entityFramework>

<providers>

<provider invariantName=“System.Data.SqlClient“ type=“System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer“ />

<provider invariantName=“System.Data.SQLite.EF6“ type=“System.Data.SQLite.EF6.SQLiteProviderServices, System.Data.SQLite.EF6“ />

</providers>

</entityFramework>

<system.data>

<DbProviderFactories>

<remove invariant=“System.Data.SQLite.EF6“ />

<add name=“SQLite Data Provider (Entity Framework 6)“ invariant=“System.Data.SQLite.EF6“ description=“.NET Framework Data Provider for SQLite (Entity Framework 6)“ type=“System.Data.SQLite.EF6.SQLiteProviderFactory, System.Data.SQLite.EF6“ />

<remove invariant=“System.Data.SQLite“ />

<add name=“SQLite Data Provider“ invariant=“System.Data.SQLite“ description=“.NET Framework Data Provider for SQLite“ type=“System.Data.SQLite.SQLiteFactory, System.Data.SQLite“ />

</DbProviderFactories>

</system.data>

<appSettings>

<add key=“channel1“ value=“500“ />

<add key=“channel2“ value=“500“ />

<add key=“channel3“ value=“500“ />

<add key=“channel4“ value=“500“ />

<add key=“channel5“ value=“500“ />

<add key=“channel6“ value=“500“ />

<add key=“channel7“ value=“500“ />

<add key=“max1“ value=“500“ />

<add key=“max2“ value=“500“ />

<add key=“max3“ value=“500“ />

<add key=“max4“ value=“500“ />

<add key=“max5“ value=“500“ />

</appSettings>

</configuration>

2.添加引用

using Configuration = System.Configuration.Configuration;

3. 声明变量

private Configuration config =ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None);

4. 读取内容

//Read System Settings: textBox20/45/48/51/54/57/60 : Display Value

textBox20.Text = ConfigurationManager.AppSettings[“channel1”] ?? “”;

textBox45.Text = ConfigurationManager.AppSettings[“channel2”] ?? “”;

textBox48.Text = ConfigurationManager.AppSettings[“channel3”] ?? “”;

textBox51.Text = ConfigurationManager.AppSettings[“channel4”] ?? “”;

textBox54.Text = ConfigurationManager.AppSettings[“channel5”] ?? “”;

textBox57.Text = ConfigurationManager.AppSettings[“channel6”] ?? “”;

textBox60.Text = ConfigurationManager.AppSettings[“channel7”] ?? “”;

5. 写入数值

通过文本框的KeyPress事件实现

private void textBox20_KeyPress(object sender, KeyPressEventArgs e)

{

string strkey = “channel1”;

if (!char.IsDigit(e.KeyChar) &&

e.KeyChar != (char)Keys.Back &&

e.KeyChar != (char)Keys.Enter)

{

e.Handled = true; //

}

if (e.KeyChar == (char)Keys.Enter)

{

textBox20.ForeColor = Color.Blue;

config.AppSettings.Settings.Remove(“channel1”);

config.AppSettings.Settings.Add(strkey, textBox20.Text);

config.Save(ConfigurationSaveMode.Modified);

ConfigurationManager.RefreshSection(“appSettings”);

}

}

6. 程序运行时，在项目文件夹—bin文件夹，会自动生成以“项目文件名.exe.config”文件，双击可以看到运行结果。