AppSettingsReader.GetValue(String, Type) 方法

定义

AppSettings 属性中获取指定键的值,并返回指定类型的对象,该对象包含来自配置文件的值。Gets the value for a specified key from the AppSettings property and returns an object of the specified type containing the value from the configuration.

public:
 System::Object ^ GetValue(System::String ^ key, Type ^ type);
public object GetValue (string key, Type type);
member this.GetValue : string * Type -> obj
Public Function GetValue (key As String, type As Type) As Object

参数

key
String

要为其获取值的键。The key for which to get the value.

type
Type

要返回的对象的类型。The type of the object to return.

返回

Object

指定键的值。The value of the specified key.

例外

keynullkey is null.

- 或 --or- typenulltype is null.

<appSettings> 配置节中不存在 keykey does not exist in the <appSettings> configuration section.

- 或 --or- key<appSettings> 配置节中的值不属于 type 类型。The value in the <appSettings> configuration section for key is not of type type.

示例

下面的示例演示如何使用 GetValue 方法在配置文件的节中检索每个键的值 <appSettings>The following example shows how to use the GetValue method to retrieve the value for each key in the <appSettings> section of the configuration file.

static void DisplayAppSettings()
{
    try
    {
        var reader = new AppSettingsReader();

        NameValueCollection appSettings = ConfigurationManager.AppSettings;

        for (int i = 0; i < appSettings.Count; i++)
        {
            string key = appSettings.GetKey(i);
            string value = (string)reader.GetValue(key, typeof(string));
            Console.WriteLine("Key : {0} Value: {1}", key, value);
        }
    }
    catch (ConfigurationErrorsException e)
    {
        Console.WriteLine("[DisplayAppSettings: {0}]", e.ToString());
    }
}
Private Shared Sub DisplayAppSettings()

    Try
        Dim reader As New AppSettingsReader()

        Dim appSettings As NameValueCollection = ConfigurationManager.AppSettings

        For i As Integer = 0 To appSettings.Count - 1
            Dim key As String = appSettings.GetKey(i)
            Dim value As String = reader.GetValue(key, GetType(String))
            Console.WriteLine("Key : {0} Value: {1}", key, value)
        Next i

    Catch e As ConfigurationErrorsException
        Console.WriteLine("[DisplayAppSettings: {0}]", e.ToString())
    End Try

End Sub

适用于

另请参阅