OracleConnectionStringBuilder.TryGetValue メソッド
アセンブリ: System.Data.OracleClient (system.data.oracleclient.dll 内)

Public Overrides Function TryGetValue ( _ keyword As String, _ <OutAttribute> ByRef value As Object _ ) As Boolean
Dim instance As OracleConnectionStringBuilder Dim keyword As String Dim value As Object Dim returnValue As Boolean returnValue = instance.TryGetValue(keyword, value)
public boolean TryGetValue ( String keyword, /** @attribute OutAttribute() */ /** @ref */ Object value )
戻り値
keyword が接続文字列に存在する場合は true。それ以外の場合は false。

TryGetValue メソッドを使用すると、有効なキー名が指定されているかどうかを検証しなくても、OracleConnectionStringBuilder から値を安全に取得できます。TryGetValue は存在しないキーを検索しても適切に処理するため、値を取得する前にそのキーが存在するかを検索する必要はありません。存在しないキーで TryGetValue を呼び出すと、value パラメータには null 値 (Visual Basic の場合は Nothing) が設定されます。

TryGetValue メソッドの動作を示す例を次に示します。
' You may need to set a reference to the System.Data.OracleClient ' assembly before you can run this sample. Imports System.Data.OracleClient Module Module1 Sub Main() Dim builder As New OracleConnectionStringBuilder() builder.ConnectionString = GetConnectionString() ' Call TryGetValue method for multiple ' key names. Note that these keys are converted ' to well-known synonynms for data retrieval. DisplayValue(builder, "Data Source") DisplayValue(builder, "trusted_connection") DisplayValue(builder, "InvalidKey") DisplayValue(builder, Nothing) Console.WriteLine("Press any key to continue.") Console.ReadLine() End Sub Private Sub DisplayValue( _ ByVal builder As OracleConnectionStringBuilder, ByVal key As String) Dim value As Object = Nothing ' Although TryGetValue handles missing keys just fine, ' it doesn't handle passing in a null (Nothing in Visual Basic) ' key. This example traps for that particular error, but ' bubbles any other unknown exceptions back out to the ' caller. Try If builder.TryGetValue(key, value) Then Console.WriteLine("{0}='{1}' ", key, value) Else Console.WriteLine("Unable to retrieve value for '{0}'", key) End If Catch ex As ArgumentNullException Console.WriteLine("Unable to retrieve value for null key.") End Try End Sub Private Function GetConnectionString() As String ' To avoid storing the connection string in your code, ' you can retrieve it from a configuration file. Return "Server=OracleDemo;Integrated Security=True" End Function End Module
// You may need to set a reference to the System.Data.OracleClient // assembly before you can run this sample. using System.Data.OracleClient; class Program { static void Main() { OracleConnectionStringBuilder builder = new OracleConnectionStringBuilder(); builder.ConnectionString = GetConnectionString(); // Call TryGetValue method for multiple // key names. Note that these keys are converted // to well-known synonynms for data retrieval. DisplayValue(builder, "Data Source"); DisplayValue(builder, "Trusted_Connection"); DisplayValue(builder, "InvalidKey"); DisplayValue(builder, null); Console.WriteLine("Press any key to continue."); Console.ReadLine(); } private static void DisplayValue(OracleConnectionStringBuilder builder, string key) { object value = null; // Although TryGetValue handles missing keys, // it does not handle passing in a null // key. This example traps for that particular error, but // passes any other unknown exceptions back out to the // caller. try { if (builder.TryGetValue(key, out value)) { Console.WriteLine("{0}='{1}'", key, value); } else { Console.WriteLine("Unable to retrieve value for '{0}'", key); } } catch (ArgumentNullException) { Console.WriteLine("Unable to retrieve value for null key."); } } private static string GetConnectionString() { // To avoid storing the connection string in your code, // you can retrieve it from a configuration file. return "Server=OracleDemo;Integrated Security=True"; } }

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