OdbcConnectionStringBuilder.ContainsKey(String) 方法
定义
重要
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确定 OdbcConnectionStringBuilder 是否包含特定键。
public:
override bool ContainsKey(System::String ^ keyword);public override bool ContainsKey (string keyword);override this.ContainsKey : string -> boolPublic Overrides Function ContainsKey (keyword As String) As Boolean参数
- keyword
- String
要在 OdbcConnectionStringBuilder 中定位的键。
返回
如果 OdbcConnectionStringBuilder 包含具有指定键的元素，则为 true；否则为 false。
例外
keyword 为 null（在 Visual Basic 中为 Nothing）。
示例
以下示例创建一个 OdbcConnectionStringBuilder 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.Odbc;
class Program
{
static void Main()
{
OdbcConnectionStringBuilder builder = new OdbcConnectionStringBuilder();
builder.Driver = "Microsoft Visual FoxPro Driver";
builder["SourceType"] = "DBC";
// Keys that you have provided return true.
Console.WriteLine(builder.ContainsKey("SourceType"));
// Comparison is case insensitive.
Console.WriteLine(builder.ContainsKey("sourcetype"));
// Keys added by the provider return false. This method
// only examines keys added explicitly.
Console.WriteLine(builder.ContainsKey("DNS"));
// Keys that do not exist return false.
Console.WriteLine(builder.ContainsKey("MyKey"));
Console.WriteLine("Press Enter to continue.");
Console.ReadLine();
}
}
Imports System.Data.Odbc
Module Module1
Sub Main()
Dim builder As New OdbcConnectionStringBuilder()
builder.Driver = "Microsoft Visual FoxPro Driver"
builder("SourceType") = "DBC"
' Keys you have provided return true.
Console.WriteLine(builder.ContainsKey("SourceType"))
' Comparison is case insensitive.
Console.WriteLine(builder.ContainsKey("sourcetype"))
' Keys added by the provider return false. This method
' only examines keys added explicitly.
Console.WriteLine(builder.ContainsKey("DNS"))
' Keys that do not exist return false.
Console.WriteLine(builder.ContainsKey("MyKey"))
Console.WriteLine("Press Enter to continue.")
Console.ReadLine()
End Sub
End Module
