本文整理汇总了C#中System.Data.SqlClient.SqlCommand.ExecuteScalarAsync方法的典型用法代码示例。如果您正苦于以下问题：C# SqlCommand.ExecuteScalarAsync方法的具体用法？C# SqlCommand.ExecuteScalarAsync怎么用？C# SqlCommand.ExecuteScalarAsync使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类System.Data.SqlClient.SqlCommand的用法示例。
在下文中一共展示了SqlCommand.ExecuteScalarAsync方法的15个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C#代码示例。
示例1: TransactionSample
private static async Task TransactionSample()
{
using (var connection = new SqlConnection(GetConnectionString()))
{
await connection.OpenAsync();
SqlTransaction tx = connection.BeginTransaction();
try
{
string sql = "INSERT INTO Sales.CreditCard (CardType, CardNumber, ExpMonth, ExpYear)" +
"VALUES (@CardType, @CardNumber, @ExpMonth, @ExpYear); " +
"SELECT SCOPE_IDENTITY()";
var command = new SqlCommand();
command.CommandText = sql;
command.Connection = connection;
command.Transaction = tx;
var p1 = new SqlParameter("CardType", SqlDbType.NVarChar, 50);
var p2 = new SqlParameter("CardNumber", SqlDbType.NVarChar, 25);
var p3 = new SqlParameter("ExpMonth", SqlDbType.TinyInt);
var p4 = new SqlParameter("ExpYear", SqlDbType.SmallInt);
command.Parameters.AddRange(new SqlParameter[] { p1, p2, p3, p4 });
command.Parameters["CardType"].Value = "MegaWoosh";
command.Parameters["CardNumber"].Value = "08154711128";
command.Parameters["ExpMonth"].Value = 4;
command.Parameters["ExpYear"].Value = 2019;
object id = await command.ExecuteScalarAsync();
WriteLine($"record added with id: {id}");
command.Parameters["CardType"].Value = "NeverLimits";
command.Parameters["CardNumber"].Value = "987654321011";
command.Parameters["ExpMonth"].Value = 12;
command.Parameters["ExpYear"].Value = 2025;
id = await command.ExecuteScalarAsync();
WriteLine($"record added with id: {id}");
// throw new Exception("abort");
tx.Commit();
}
catch (Exception ex)
{
WriteLine($"error {ex.Message}, rolling back");
tx.Rollback();
}
}
}示例2: Check
public override async Task<HealthCheckStatus> Check()
{
using (var connection = new SqlConnection(_connectionString))
{
await connection.OpenAsync().ConfigureAwait(false);
var cmd = new SqlCommand("select 1", connection);
await cmd.ExecuteScalarAsync().ConfigureAwait(false);
return HealthCheckStatus.Passed();
}
}示例3: Insert
public static async Task Insert( this Tag NewTag, SqlConnection Connection, SqlTransaction Transaction = null ) {
using( SqlCommand Command = new SqlCommand() ) {
Command.Connection = Connection;
if( null != Transaction ) Command.Transaction = Transaction;
Command.CommandText = "INSERT Tags ( Text ) OUTPUT INSERTED.Id VALUES ( @Text )";
Command.Parameters.Add( "Text", System.Data.SqlDbType.VarChar ).Value = NewTag.Text;
NewTag.Id = (short)await Command.ExecuteScalarAsync();
}
}示例4: GetLastId
public Task<long?> GetLastId()
{
var connection = CreateAndOpenConnection();
var transaction = connection.BeginTransaction(System.Data.IsolationLevel.ReadUncommitted);
var cmd = new SqlCommand(_getLastIdSQL.Replace("{TableName}", MessageTableName), connection, transaction);
return cmd.ExecuteScalarAsync<long?>()
.ContinueWith(t =>
{
connection.Close();
return t.Result;
});
}示例5: NonBlockingDatabaseOperations
/// <summary>
/// Performs a sequence of non blocking database operations.
/// </summary>
private async static Task NonBlockingDatabaseOperations()
{
// Build the database connection.
using (SqlConnection sqlConnection = new SqlConnection(ConfigurationManager.ConnectionStrings["SampleHttpApplication"].ConnectionString))
{
// Open the database connection.
await sqlConnection.OpenAsync();
// Insert the database row.
SqlCommand insertSqlCommand = new SqlCommand("INSERT INTO [Session] VALUES('" + Guid.NewGuid() + "', 'Session Alpha', '2012-06-27 10:05:45'); SELECT CAST(SCOPE_IDENTITY() AS INT);", sqlConnection);
int sessionID = (int)await insertSqlCommand.ExecuteScalarAsync();
// Select the database row.
SqlCommand selectSqlCommand = new SqlCommand("SELECT * FROM [Session] WHERE [SessionID] = " + sessionID, sqlConnection);
SqlDataReader sqlDataReader = await selectSqlCommand.ExecuteReaderAsync();
await sqlDataReader.ReadAsync();
sqlDataReader.Close();
// Update the database row.
SqlCommand updateSqlCommand = new SqlCommand("UPDATE [Session] SET [SessionCode] = '" + Guid.NewGuid() + "', [Name] = 'Session Beta', [StartDate] = '2013-07-28 11:06:46' WHERE [SessionID] = " + sessionID, sqlConnection);
await updateSqlCommand.ExecuteNonQueryAsync();
// Delete the database row.
SqlCommand deleteSqlCommand = new SqlCommand("DELETE FROM [Session] WHERE [SessionID] = " + sessionID, sqlConnection);
await deleteSqlCommand.ExecuteNonQueryAsync();
}
}示例6: GenerateMessageId
public Task<long> GenerateMessageId(string key)
{
var connection = CreateAndOpenConnection();
var transaction = connection.BeginTransaction(IsolationLevel.ReadUncommitted);
var cmd = new SqlCommand(_getMessageIdSql.Replace("{TableName}", MessageTableName), connection, transaction);
cmd.Parameters.AddWithValue("EventKey", key);
return cmd.ExecuteScalarAsync<long>()
.ContinueWith(idTask =>
{
// We purposely don't commit the transaction, we just wanted the ID anyway, not the record
connection.Close();
return idTask;
})
.Unwrap();
}示例7: Register
public async Task<bool> Register()
{
bool success = false;
Exception err = null;
string sql = "INSERT INTO dbo.Users (facebook_id, gender, email, name, first_name, last_name, isAnonymous) OUTPUT INSERTED.id VALUES (@facebook_id, @gender, @email, @name, @first_name, @last_name, @isAnonymous)";
if (db.State != ConnectionState.Open)
await db.OpenAsync();
SqlTransaction trans = db.BeginTransaction();
try
{
SqlCommand cmd = new SqlCommand(sql, db, trans);
cmd.Parameters.AddWithValue("@facebook_id", facebook_id);
cmd.Parameters.AddWithValue("@gender", gender);
cmd.Parameters.AddWithValue("@email", email);
cmd.Parameters.AddWithValue("@name", name);
cmd.Parameters.AddWithValue("@last_name", last_name);
cmd.Parameters.AddWithValue("@first_name", first_name);
cmd.Parameters.AddWithValue("@isAnonymous", isAnonymous);
object id = await cmd.ExecuteScalarAsync();
if (id != null && id.GetType() == typeof(Guid))
{
this.id = ((Guid)id);
success = true;
}
trans.Commit();
}
catch (Exception e)
{
err = e;
trans.Rollback();
}
finally
{
db.Close();
}
if (err != null)
{
throw err;
}
return success;
}示例8: Create
public async Task<bool> Create()
{
bool success = false;
Exception err = null;
string sql = "INSERT INTO dbo.ItemLists (name, description, status, created_by, category, category_id, group_id) OUTPUT INSERTED.id VALUES (@name, @description, @status, @created_by, @category, @category_id, @group_id)";
if (db.State != ConnectionState.Open)
await db.OpenAsync();
SqlTransaction trans = db.BeginTransaction();
try
{
SqlCommand cmd = new SqlCommand(sql, db, trans);
cmd.Parameters.AddWithValue("@name", name);
cmd.Parameters.AddWithValue("@description", description);
cmd.Parameters.AddWithValue("@status", status);
cmd.Parameters.AddWithValue("@created_by", created_by);
cmd.Parameters.AddWithValue("@category", category);
cmd.Parameters.AddWithValue("@category_id", category_id);
cmd.Parameters.AddWithValue("@group_id", group_id);
object id = await cmd.ExecuteScalarAsync();
if (id != null && id.GetType() == typeof(Guid))
{
this.id = ((Guid)id);
success = true;
}
trans.Commit();
}
catch (Exception e)
{
err = e;
trans.Rollback();
}
finally
{
db.Close();
}
if (err != null)
{
throw err;
}
this.created_at = DateTime.Now;
return success;
}示例9: LinkDevice
public async Task<bool> LinkDevice()
{
bool success = false;
Exception err = null;
string sql = "INSERT INTO dbo.DeviceOwners (device_id, user_id) OUTPUT INSERTED.id VALUES (@device_id, @user_id)";
if (db.State != ConnectionState.Open)
await db.OpenAsync();
SqlTransaction trans = db.BeginTransaction();
try
{
SqlCommand cmd = new SqlCommand(sql, db, trans);
cmd.Parameters.AddWithValue("@device_id", device.id);
cmd.Parameters.AddWithValue("@user_id", user.id);
object id = await cmd.ExecuteScalarAsync();
if (id != null && id.GetType() == typeof(Guid))
{
this.id = ((Guid)id);
success = true;
this.linked_at = DateTime.Now;
}
trans.Commit();
}
catch (Exception e)
{
err = e;
trans.Rollback();
}
finally
{
db.Close();
}
if (err != null)
{
throw err;
}
return success;
}示例10: Create
/// <summary>
/// Creates the specified CourseSchedule data row.
/// </summary>
public async Task Create(IDatabaseConnection databaseConnection, CourseScheduleDataRow courseScheduleDataRow)
{
// Build the SQL command.
using (SqlCommand sqlCommand = new SqlCommand("INSERT INTO [CourseSchedule] VALUES (@courseScheduleCode, @sessionID, @dayOfWeek, @time); SELECT CAST(SCOPE_IDENTITY() AS INT);"))
{
// Use the specified database connection.
SqlConnection sqlConnection = (databaseConnection as DatabaseConnection).SqlConnection;
sqlCommand.Connection = sqlConnection;
// Set the SQL command parameter values.
this.SetSqlCommandParameterValues(sqlCommand, courseScheduleDataRow, setPrimaryKeyValue: false);
// Execute the SQL command.
int courseScheduleID = (int)await sqlCommand.ExecuteScalarAsync();
// Assign the generated CourseScheduleID.
courseScheduleDataRow.CourseScheduleID = courseScheduleID;
}
}示例11: Create
public async Task<bool> Create()
{
bool success = false;
Exception err = null;
string sql = "INSERT INTO dbo.Memberships (user_id, group_id, status) OUTPUT INSERTED.id VALUES (@user_id, @group_id, @status)";
if (db.State != ConnectionState.Open)
await db.OpenAsync();
SqlTransaction trans = db.BeginTransaction();
try
{
SqlCommand cmd = new SqlCommand(sql, db, trans);
cmd.Parameters.AddWithValue("@user_id", user_id);
cmd.Parameters.AddWithValue("@group_id", group_id);
cmd.Parameters.AddWithValue("@status", status);
object id = await cmd.ExecuteScalarAsync();
if (id != null && id.GetType() == typeof(Guid))
{
this.id = ((Guid)id);
success = true;
}
trans.Commit();
}
catch (Exception e)
{
err = e;
trans.Rollback();
}
finally
{
db.Close();
}
if (err != null)
{
throw err;
}
return success;
}示例12: Create
/// <summary>
/// Creates the specified Session data row.
/// </summary>
public async Task Create(IDatabaseConnection databaseConnection, SessionDataRow sessionDataRow)
{
// Build the SQL command.
using (SqlCommand sqlCommand = new SqlCommand("INSERT INTO [Session] VALUES (@sessionCode, @name, @startDate); SELECT CAST(SCOPE_IDENTITY() AS INT);"))
{
// Use the specified database connection.
SqlConnection sqlConnection = (databaseConnection as DatabaseConnection).SqlConnection;
sqlCommand.Connection = sqlConnection;
// Set the SQL command parameter values.
this.SetSqlCommandParameterValues(sqlCommand, sessionDataRow, setPrimaryKeyValue: false);
// Execute the SQL command.
int sessionID = (int)await sqlCommand.ExecuteScalarAsync();
// Assign the generated SessionID.
sessionDataRow.SessionID = sessionID;
}
}示例13: Load
public async Task<object> Load(Type valueType, string user, string name, Type storageType)
{
const string sql =
"SELECT [Value] " +
"FROM [dbo].[Settings] " +
"WHERE [Type] = @Type " +
" AND (@User IS NULL OR [User] = @User) " +
" AND (@Name IS NULL OR [Name] = @Name)";
using (var connection = CreateConnection())
{
var command = new SqlCommand(sql, connection);
command.Parameters.AddWithValue("@Type", valueType.FullName);
command.Parameters.AddWithValue("@User", (object)user ?? DBNull.Value);
command.Parameters.AddWithValue("@Name", (object)name ?? DBNull.Value);
var value = await command.ExecuteScalarAsync();
return Convert.ChangeType(value, storageType);
}
}示例14: SaveFileMetaDataAsync
/// <inheritdoc/>
public async Task<int> SaveFileMetaDataAsync(FileMetaDataToStore metaData)
{
int fileId;
using (var connection = new SqlConnection(connectionString))
{
using (var command = new SqlCommand("InsertFileMetaData", connection))
{
command.CommandType = CommandType.StoredProcedure;
command.Parameters.AddWithValue("@FileName", metaData.FileName);
command.Parameters.AddWithValue("@MimeType", metaData.MimeType);
command.Parameters.AddWithValue("@ApplicationName", metaData.ApplicationName);
command.Parameters.AddWithValue("@InternalStoragePath", metaData.StoragePath);
command.Parameters.AddWithValue("@Checksum", metaData.Checksum);
await connection.OpenAsync();
fileId = Convert.ToInt32(await command.ExecuteScalarAsync());
}
}
return fileId;
}示例15: WriteZonesAsync
private static async Task<IDictionary<string, int>> WriteZonesAsync(IEnumerable<string> zones)
{
var dictionary = new Dictionary<string, int>();
var cs = ConfigurationManager.ConnectionStrings["tzdb"].ConnectionString;
using (var connection = new SqlConnection(cs))
{
var command = new SqlCommand("[Tzdb].[AddZone]", connection) { CommandType = CommandType.StoredProcedure };
command.Parameters.Add("@Name", SqlDbType.VarChar, 50);
await connection.OpenAsync();
foreach (var zone in zones)
{
command.Parameters[0].Value = zone;
var id = (int)await command.ExecuteScalarAsync();
dictionary.Add(zone, id);
}
connection.Close();
}
return dictionary;
}