OleDbConnectionStringBuilder.Clear 方法

定义

命名空间:

System.Data.OleDb

程序集:

System.Data.OleDb.dll

包:

System.Data.OleDb v8.0.0

Source:

OleDbConnectionStringBuilder.cs

清除 OleDbConnectionStringBuilder 实例的内容。

public:
 override void Clear();

public override void Clear ();

override this.Clear : unit -> unit

Public Overrides Sub Clear ()

示例

以下示例演示了调用 Clear 方法的效果。 此示例用一些键/值对填充 OleDbConnectionStringBuilder，然后调用 Clear 方法并显示结果。

注意

该示例包括一个密码以演示 OleDbConnectionStringBuilder 如何使用连接字符串。 在您的应用程序中，建议使用 Windows 身份验证。 如果必须使用密码，请不要在你的应用程序中包括硬编码的密码。

using System.Data.OleDb;

class Program
{
    static void Main()
    {
        OleDbConnectionStringBuilder builder =
            new OleDbConnectionStringBuilder();
        builder.ConnectionString = @"Data Source=c:\Sample.mdb";

        // Call the Add method to explicitly add key/value
        // pairs to the internal collection.
        builder.Add("Provider", "Microsoft.Jet.Oledb.4.0");
        builder.Add("Jet OLEDB:Database Password", "MyPassword!");
        builder.Add("Jet OLEDB:System Database", @"C:\Workgroup.mdb");

        // set up row-level locking.
        builder.Add("Jet OLEDB:Database Locking Mode", 1);

        // Dump the contents of the "filled-in"
        // OleDbConnectionStringBuilder
        // to the console window.
        DumpBuilderContents(builder);

        // Clear current values and reset known keys to their
        // default values.
        builder.Clear();

        // Dump the contents of the newly emptied
        // OleDbConnectionStringBuilder
        // to the console window.
        DumpBuilderContents(builder);

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

    private static void DumpBuilderContents(OleDbConnectionStringBuilder builder)
    {
        Console.WriteLine("=================");
        Console.WriteLine("builder.ConnectionString = " + builder.ConnectionString);
        foreach (string key in builder.Keys)
        {
            Console.WriteLine(key + "=" + builder[key].ToString());
        }
    }
}

Imports System.Data.OleDb    

Module Module1
  Sub Main()
    Dim builder As New OleDbConnectionStringBuilder()
    builder.ConnectionString = "Data Source=C:\Sample.mdb"

    ' Call the Add method to explicitly add key/value
    ' pairs to the internal collection.
    builder.Add("Provider", "Microsoft.Jet.Oledb.4.0")
    builder.Add("Jet OLEDB:Database Password", "MyPassword!")
    builder.Add("Jet OLEDB:System Database", "C:\Workgroup.mdb")

    ' Set up row-level locking.
    builder.Add("Jet OLEDB:Database Locking Mode", 1)

    ' Dump the contents of the "filled-in" OleDbConnectionStringBuilder
    ' to the console window.
    DumpBuilderContents(builder)

    ' Clear current values and reset known keywords to their
    ' default values.
    builder.Clear()

    ' Dump the contents of the newly emptied 
    ' OleDbConnectionStringBuilder
    ' to the console window.
    DumpBuilderContents(builder)

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

  Private Sub DumpBuilderContents(ByVal builder As OleDbConnectionStringBuilder)
    Console.WriteLine("=================")
    Console.WriteLine("builder.ConnectionString = " & builder.ConnectionString)
    For Each key As String In builder.Keys
      Console.WriteLine(key & "=" & builder.Item(key).ToString)
    Next
  End Sub
End Module

注解

方法 Clear 从 OleDbConnectionStringBuilder中删除所有键/值对，并将所有相应的属性重置为其默认值。 这包括将 Count 属性设置为 0，并将 ConnectionString 属性设置为空字符串。

另请参阅

• 连接字符串生成器
• ADO.NET 中的连接字符串