OleDbConnectionStringBuilder.Clear 方法
定义
重要
一些信息与预发行产品相关,相应产品在发行之前可能会进行重大修改。 对于此处提供的信息,Microsoft 不作任何明示或暗示的担保。
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。