QueryResult 类

表示从数据库查询返回的查询结果。

继承等级结构

System.Object
Microsoft.Web.Management.DatabaseManager.QueryResult

Namespace： Microsoft.Web.Management.DatabaseManager
程序集： Microsoft.Web.Management.DatabaseManager （Microsoft.Web.Management.DatabaseManager.dll）

语法

'Declaration
Public Class QueryResult
'Usage
Dim instance As QueryResult

public class QueryResult

public ref class QueryResult

public class QueryResult

QueryResult 类型公开以下成员。

构造函数

方法类型	名称	描述
	QueryResult	创建 QueryResult 类的新实例。

属性

属性类型	名称	描述
	ColumnMetadata	返回查询结果的列元数据列表。
	QueryResults	检索查询结果数组。

方法

方法类型	名称	描述
	等于	（从 Object 继承。）
	完成	（从 Object 继承。）
	GetHashCode	（从 Object 继承。）
	GetType	（从 Object 继承。）
	MemberwiseClone	（从 Object 继承。）
	ToString	（从 Object 继承。）

示例

下面的代码示例演示了一个从数据库查询返回查询结果数组的示例 ExecuteQuery 方法。

    Public Overrides Function ExecuteQuery( _
            ByVal connectionString As String, _
            ByVal query As Microsoft.Web.Management.DatabaseManager.Query) _
            As Microsoft.Web.Management.DatabaseManager.QueryResult()

        Dim results As List(Of QueryResult) = New List(Of QueryResult)
        Dim result As QueryResult = New QueryResult
        Try
            ' Create a new OLEDB connection using the connection string.
            Dim connection As OleDbConnection = New OleDbConnection(connectionString)
            Dim command As OleDbCommand = New OleDbCommand(query.Statement, connection)
            ' Open the database connection.
            connection.Open()
            ' Execute the query and access the data.
            Dim reader As OleDbDataReader = command.ExecuteReader
            ' Add the results to the query list.
            results.Add(GetQueryResult(reader))
            ' Close the database connection.
            reader.Close()
            ' Return the query results.
            Return results.ToArray
        Catch ex As Exception
            Throw New ProviderException(ex.Message)
        End Try

    End Function



...



    Private Function GetQueryResult(ByVal reader As OleDbDataReader) As QueryResult
        Dim result As QueryResult = New QueryResult
        Dim fieldCount As Integer = reader.FieldCount
        Dim i As Integer = 0
        Do While (i < fieldCount)
            Dim metadata As QueryColumnMetadata = New QueryColumnMetadata
            metadata.Name = reader.GetName(i)
            result.ColumnMetadata.Add(metadata)
            i = (i + 1)
        Loop

        While reader.Read
            Dim itemData() As Object = New Object((fieldCount) - 1) {}
            i = 0
            Do While (i < fieldCount)
                itemData(i) = ConvertToSerializable(reader(i))
                i = (i + 1)
            Loop
            result.QueryResults.Add(itemData)

        End While
        Return result
    End Function

        public override QueryResult[] ExecuteQuery(
            string connectionString,
            Query query )
        {
            List<QueryResult> results = new List<QueryResult>();
            QueryResult result = new QueryResult();
            try
            {
                // Create a new OLEDB connection using the connection string.
                using (OleDbConnection connection = new OleDbConnection(connectionString))
                {
                    OleDbCommand command = new OleDbCommand(query.Statement, connection);
                    // Open the database connection.
                    connection.Open();
                    // Execute the query and access the data.
                    OleDbDataReader reader = command.ExecuteReader();
                    // Add the results to the query list.
                    results.Add(GetQueryResult(reader));
                    // Close the database connection.
                    reader.Close();
                }
                // Return the query results.
                return results.ToArray();
            }
            catch(Exception ex)
            {
                throw new ProviderException(ex.Message);
            }
        }



...



        private QueryResult GetQueryResult(OleDbDataReader reader)
        {
            QueryResult result = new QueryResult();
            int fieldCount = reader.FieldCount;

            for (int i = 0; i < fieldCount; i++)
            {
                QueryColumnMetadata metadata = new QueryColumnMetadata();
                metadata.Name = reader.GetName(i);
                result.ColumnMetadata.Add(metadata);
            }

            while (reader.Read())
            {
                object[] itemData = new object[fieldCount];
                for (int i = 0; i < fieldCount; i++)
                {
                    itemData[i] = ConvertToSerializable(reader[i]);
                }
                result.QueryResults.Add(itemData);
            }
            return result;
        }

线程安全

此类型的所有公共静态（在 Visual Basic 中为Shared）成员都是线程安全的。 但不保证所有实例成员都是线程安全的。

另请参阅

参考

Microsoft.Web.Management.DatabaseManager 命名空间