SqlConnectionStringBuilder.ContainsKey(String) 方法

定义

命名空间:

System.Data.SqlClient

程序集:

System.Data.dll

确定 SqlConnectionStringBuilder 是否包含特定键。

public:
 override bool ContainsKey(System::String ^ keyword);

public override bool ContainsKey (string keyword);

override this.ContainsKey : string -> bool

Public Overrides Function ContainsKey (keyword As String) As Boolean

参数

keyword

String

要在 SqlConnectionStringBuilder 中定位的键。

返回

Boolean

如果 SqlConnectionStringBuilder 包含具有指定键的元素，则为 true；否则为 false。

例外

ArgumentNullException

keyword 为 Null（在 Visual Basic 中为 Nothing）

示例

以下示例创建一个 SqlConnectionStringBuilder 实例，设置其一些属性，然后尝试通过调用 ContainsKey 方法来确定对象中是否存在各种键。

using System.Data.SqlClient;

class Program
{
    static void Main()
    {
        SqlConnectionStringBuilder builder =
            new SqlConnectionStringBuilder(GetConnectionString());
        Console.WriteLine("Connection string = " + builder.ConnectionString);

        // Keys you have provided return true.
        Console.WriteLine(builder.ContainsKey("Server"));

        // Comparison is case insensitive, and synonyms
        // are automatically converted to their "well-known"
        // names.
        Console.WriteLine(builder.ContainsKey("Database"));

        // Keys that are valid but have not been set return true.
        Console.WriteLine(builder.ContainsKey("Max Pool Size"));

        // Keys that do not exist return false.
        Console.WriteLine(builder.ContainsKey("MyKey"));

        Console.WriteLine("Press Enter to continue.");
        Console.ReadLine();
    }

    private static string GetConnectionString()
    {
        // To avoid storing the connection string in your code,
        // you can retrieve it from a configuration file.
        return "Server=(local);Integrated Security=SSPI;" +
            "Initial Catalog=AdventureWorks";
    }
}

Imports System.Data.SqlClient

Module Module1
    Sub Main()
        Dim builder As _
         New SqlConnectionStringBuilder(GetConnectionString())
        Console.WriteLine("Connection string = " & builder.ConnectionString)

        ' Keys you have provided return true.
        Console.WriteLine(builder.ContainsKey("Server"))

        ' Comparison is case insensitive, and synonyms
        ' are automatically converted to their "well-known"
        ' names.
        Console.WriteLine(builder.ContainsKey("Database"))

        ' Keys that are valid but have not been set return true.
        Console.WriteLine(builder.ContainsKey("Max Pool Size"))

        ' Keys that do not exist return false.
        Console.WriteLine(builder.ContainsKey("MyKey"))

        Console.WriteLine("Press Enter to continue.")
        Console.ReadLine()
    End Sub

    Private Function GetConnectionString() As String
        ' To avoid storing the connection string in your code,
        ' you can retrieve it from a configuration file. 
        Return "Server=(local);Integrated Security=SSPI;" & _
          "Initial Catalog=AdventureWorks"
    End Function
End Module

该示例在控制台窗口中显示以下输出：

Connection string = Data Source=(local);Initial Catalog=AdventureWorks;Integrated Security=True
True
True
True
False

注解

由于 SqlConnectionStringBuilder 包含固定大小的键/值对集合，因此 ContainsKey 方法只确定特定键名是否有效。

另请参阅

• ADO.NET 中的连接字符串
• ADO.NET 概述