DbConnectionStringBuilder.ContainsKey(String) 方法

定义

命名空间:

System.Data.Common

程序集:

System.Data.Common.dll

Source:

DbConnectionStringBuilder.cs

确定 DbConnectionStringBuilder 是否包含特定键。

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

public virtual bool ContainsKey (string keyword);

abstract member ContainsKey : string -> bool
override this.ContainsKey : string -> bool

Public Overridable Function ContainsKey (keyword As String) As Boolean

参数

keyword

String

要在 DbConnectionStringBuilder 中定位的键。

返回

Boolean

如果 DbConnectionStringBuilder 包含具有指定键的项，则为 true；否则为 false。

例外

ArgumentNullException

keyword 为空引用（在 Visual Basic 中为 Nothing）。

示例

static void Main()
{
    DbConnectionStringBuilder builder = new DbConnectionStringBuilder();
    builder.Add("Provider", "Provider=Microsoft.Jet.OLEDB.4.0");
    builder.Add("Data Source", "C:\\ThisExcelWorkbook.xls");
    builder.Add("Extended Properties", "Excel 8.0;HDR=Yes;IMEX=1");

    // Displays the values in the DbConnectionStringBuilder.
    Console.WriteLine("Contents of the DbConnectionStringBuilder:");
    Console.WriteLine(builder.ConnectionString);

    // Searches for a key.
    if (builder.ContainsKey("Data Source"))
    {
        Console.WriteLine("The collection contains the key \"Data Source\".");
    }
    else
    {
        Console.WriteLine("The collection does not contain the key \"Data Source\".");
    }
    Console.ReadLine();
}

Sub Main()
    ' The following code example searches for an element in a 
    ' DbConnectionStringBuilder.
    Dim builder As New DbConnectionStringBuilder
    builder.Add("Provider", "Provider=Microsoft.Jet.OLEDB.4.0")
    builder.Add("Data Source", "C:\ThisExcelWorkbook.xls")
    builder.Add("Extended Properties", "Excel 8.0;HDR=Yes;IMEX=1")

    ' Displays the values in the DbConnectionStringBuilder.
    Console.WriteLine("Contents of the DbConnectionStringBuilder:")
    Console.WriteLine(builder.ConnectionString)

    ' Searches for a key.
    If builder.ContainsKey("Data Source") Then
        Console.WriteLine("The collection contains the key ""Data Source"".")
    Else
        Console.WriteLine("The collection does not contain the key ""Data Source"".")
    End If
    Console.ReadLine()
End Sub

此代码生成以下输出：

Contents of the DbConnectionStringBuilder:
provider="Provider=Microsoft.Jet.OLEDB.4.0";data
source=C:\MyExcel.xls;extended
properties="Excel 8.0;HDR=Yes;IMEX=1"
The collection contains the key "Data Source".

另请参阅

• ADO.NET 中的连接字符串
• ADO.NET 概述