OleDbConnectionStringBuilder.Item[String] 属性

定义

命名空间:

System.Data.OleDb

程序集:

System.Data.OleDb.dll

包:

System.Data.OleDb v11.0.0-preview.2.26159.112

Source:

OleDbConnectionStringBuilder.cs

获取或设置与指定键关联的值。 在 C# 中，此属性是索引器。

public:
 virtual property System::Object ^ default[System::String ^] { System::Object ^ get(System::String ^ keyword); void set(System::String ^ keyword, System::Object ^ value); };

public override object this[string keyword] { get; set; }

member this.Item(string) : obj with get, set

Default Public Overrides Property Item(keyword As String) As Object

参数

keyword

String

要获取或设置的项的键。

属性值

Object

与指定键关联的值。

例外

ArgumentException

连接字符串的格式不正确（可能缺少键/值对中所需的“=”。

ArgumentNullException

keyword 是 null 引用（Nothing 在 Visual Basic 中）。

示例

下面的示例使用 Item[] 属性（索引器，以 C# 为单位）检索和设置键/值对集合中的值。 请注意，在这种情况下，设置提供程序还为与所选提供程序关联的所有键/值对提供默认值。

using System.Data.OleDb;

class Program
{
    static void Main()
    {
        OleDbConnectionStringBuilder builder = new OleDbConnectionStringBuilder();
        builder.Provider = "Microsoft.Jet.Oledb.4.0";
        builder.DataSource = @"C:\Sample.mdb";
        // Set properties using the Item property (the indexer, in C#).
        builder["Jet OLEDB:Encrypt Database"] = true;
        builder["Jet OLEDB:System database"] = @"C:\Workgroup.mdw";

        Console.WriteLine(builder.ConnectionString);
        Console.WriteLine();

        // Use the Item property to retrieve values as well.
        Console.WriteLine(builder["Jet OLEDB:System database"]);
        Console.WriteLine(builder["Jet OLEDB:Encrypt Database"]);

        // You can set or retrieve any of the "default" values for the
        // provider, even if you didn't set their values.
        Console.WriteLine(builder["Jet OLEDB:Database Locking Mode"]);
        Console.WriteLine(builder["Jet OLEDB:Global Partial Bulk Ops"]);

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

Imports System.Data.OleDb

Module Module1
  Sub Main()
    Dim builder As New OleDbConnectionStringBuilder
    builder.Provider = "Microsoft.Jet.Oledb.4.0"
    builder.DataSource = "C:\Sample.mdb"
    ' Set properties using the Item property.
    builder.Item("Jet OLEDB:Encrypt Database") = True

    ' Because Item is the default property, you can leave out
    ' the explicit reference.
    builder("Jet OLEDB:System database") = "C:\Workgroup.mdw"

    Console.WriteLine(builder.ConnectionString)
    Console.WriteLine()

    ' Use the Item property to retrieve values, as well.
    Console.WriteLine(builder.Item("Jet OLEDB:System database"))
    Console.WriteLine(builder("Jet OLEDB:Encrypt Database"))

    ' You can set or retrieve any of the "default" values for the
    ' provider, as well, even if you did not set their values. Again,
    ' explicitly specifying the Item property name is optional.
    Console.WriteLine(builder.Item("Jet OLEDB:Database Locking Mode"))
    Console.WriteLine(builder("Jet OLEDB:Global Partial Bulk Ops"))

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

注解

由于设置 Provider 该属性可能会将相应的项添加到键/值对集合（具体取决于特定提供程序的行为），因此你也许能够检索尚未显式设置的键的值。 例如，只要将 Provider 属性设置为“sqloledb”，即使尚未自行设置，也可以检索“工作站 ID”值。 有关演示，请参阅本主题中的示例。

另请参阅

• 连接字符串生成器
• ADO.NET 中的连接字符串