CommandHelper.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / fx / src / DataEntity / System / Data / Common / Utils / CommandHelper.cs / 1305376 / CommandHelper.cs
                        
                        
                            //---------------------------------------------------------------------- 
// 
//      Copyright (c) Microsoft Corporation.  All rights reserved.
// 
// 
// @owner [....]
// @backupOwner [....] 
//--------------------------------------------------------------------- 

using System.Diagnostics; 
using System.Data.Metadata.Edm;
using System.Data.EntityClient;
using System.Data.Objects;
namespace System.Data.Common.Utils 
{
    ///  
    /// Contains utility methods for construction of DB commands through generic 
    /// provider interfaces.
    ///  
    internal static class CommandHelper
    {
        /// 
        /// Consumes all rows and result sets from the reader. This allows client to retrieve 
        /// parameter values and intercept any store exceptions.
        ///  
        /// reader to consume 
        internal static void ConsumeReader(DbDataReader reader)
        { 
            if (null != reader && !reader.IsClosed)
            {
                while (reader.NextResult())
                { 
                    // Note that we only walk through the result sets. We don't need
                    // to walk through individual rows (though underlying provider 
                    // implementation may do so) 
                }
            } 
        }

        /// 
        /// requires: commandText must not be null 
        /// The command text must be in the form Container.FunctionImportName.
        ///  
        internal static void ParseFunctionImportCommandText(string commandText, string defaultContainerName, out string containerName, out string functionImportName) 
        {
            Debug.Assert(null != commandText); 

            // Split the string
            string[] nameParts = commandText.Split('.');
            containerName = null; 
            functionImportName = null;
            if (2 == nameParts.Length) 
            { 
                containerName = nameParts[0].Trim();
                functionImportName = nameParts[1].Trim(); 
            }
            else if (1 == nameParts.Length && null != defaultContainerName)
            {
                containerName = defaultContainerName; 
                functionImportName = nameParts[0].Trim();
            } 
            if (string.IsNullOrEmpty(containerName) || string.IsNullOrEmpty(functionImportName)) 
            {
                throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.EntityClient_InvalidStoredProcedureCommandText); 
            }
        }

        ///  
        /// Given an entity command, returns the associated entity transaction and performs validation
        /// to ensure the transaction is consistent. 
        ///  
        /// Entity command instance. Must not be null.
        /// Entity transaction 
        internal static EntityTransaction GetEntityTransaction(EntityCommand entityCommand)
        {
            Debug.Assert(null != entityCommand);
            EntityTransaction entityTransaction = (EntityTransaction)entityCommand.Transaction; 

            // Check to make sure that either the command has no transaction associated with it, or it 
            // matches the one used by the connection 
            if (entityTransaction != null && entityTransaction != entityCommand.Connection.CurrentTransaction)
            { 
                throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.EntityClient_InvalidTransactionForCommand);
            }
            // Now we have asserted that EntityCommand either has no transaction or has one that matches the
            // one used in the connection, we can simply use the connection's transaction object 
            entityTransaction = entityCommand.Connection.CurrentTransaction;
            return entityTransaction; 
        } 

 
        /// 
        /// Given an entity command and entity transaction, passes through relevant state to store provider
        /// command.
        ///  
        /// Entity command. Must not be null.
        /// Entity transaction. Must not be null. 
        /// Store provider command that is being setup. Must not be null. 
        internal static void SetStoreProviderCommandState(EntityCommand entityCommand, EntityTransaction entityTransaction, DbCommand storeProviderCommand)
        { 
            Debug.Assert(null != entityCommand);
            Debug.Assert(null != storeProviderCommand);

            storeProviderCommand.CommandTimeout = entityCommand.CommandTimeout; 
            storeProviderCommand.Connection = ((EntityConnection)entityCommand.Connection).StoreConnection;
            storeProviderCommand.Transaction = (null != entityTransaction) ? entityTransaction.StoreTransaction : null; 
            storeProviderCommand.UpdatedRowSource = entityCommand.UpdatedRowSource; 
        }
 

        /// 
        /// Given an entity command and store provider command, sets all output parameter values on the entity command.
        ///  
        /// Entity command on which to set parameter values. Must not be null.
        /// Store provider command from which to retrieve parameter values. Must not 
        /// be null. 
        internal static void SetEntityParameterValues(EntityCommand entityCommand, DbCommand storeProviderCommand)
        { 
            Debug.Assert(null != entityCommand);
            Debug.Assert(null != storeProviderCommand);

            foreach (DbParameter storeParameter in storeProviderCommand.Parameters) 
            {
                ParameterDirection direction = storeParameter.Direction; 
                if (0 != (direction & ParameterDirection.Output)) 
                {
                    // if the entity command also defines the parameter, propagate store parameter value 
                    // to entity parameter
                    int parameterOrdinal = entityCommand.Parameters.IndexOf(storeParameter.ParameterName);
                    if (0 <= parameterOrdinal)
                    { 
                        EntityParameter entityParameter = entityCommand.Parameters[parameterOrdinal];
                        entityParameter.Value = storeParameter.Value; 
                    } 
                }
            } 
        }

        // requires: all arguments must be given
        internal static EdmFunction FindFunctionImport(MetadataWorkspace workspace, string containerName, string functionImportName) 
        {
            Debug.Assert(null != workspace && null != containerName && null != functionImportName); 
            // find entity container 
            EntityContainer entityContainer;
            if (!workspace.TryGetEntityContainer(containerName, DataSpace.CSpace, out entityContainer)) 
            {
                throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.EntityClient_UnableToFindFunctionImportContainer(
                    containerName));
            } 

            // find function import 
            EdmFunction functionImport = null; 
            foreach (EdmFunction candidate in entityContainer.FunctionImports)
            { 
                if (candidate.Name == functionImportName)
                {
                    functionImport = candidate;
                    break; 
                }
            } 
            if (null == functionImport) 
            {
                throw EntityUtil.InvalidOperation(System.Data.Entity.Strings.EntityClient_UnableToFindFunctionImport( 
                    containerName, functionImportName));
            }
            return functionImport;
        } 
    }
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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CommandHelper.cs source code in C# .NET

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