C#数据库操作类

public abstract class SqlHelper {

//Database connection strings
public static readonly string ConnectionStringLocalTransaction = ConfigurationManager.ConnectionStrings["SQLConnString1"].ConnectionString;

private static Hashtable parmCache = Hashtable.Synchronized(new Hashtable());

public static int ExecuteNonQuery(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
 SqlCommand cmd = new SqlCommand();

using (SqlConnection conn = new SqlConnection(connectionString)) {
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}
}

public static int ExecuteNonQuery(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {

SqlCommand cmd = new SqlCommand();

PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}

 public static int ExecuteNonQuery(SqlTransaction trans, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
SqlCommand cmd = new SqlCommand();
PrepareCommand(cmd, trans.Connection, trans, cmdType, cmdText, commandParameters);
int val = cmd.ExecuteNonQuery();
cmd.Parameters.Clear();
return val;
}

public static SqlDataReader ExecuteReader(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
SqlCommand cmd = new SqlCommand();
SqlConnection conn = new SqlConnection(connectionString);
try {
PrepareCommand(cmd, conn, null, cmdType, cmdText, commandParameters);
SqlDataReader rdr = cmd.ExecuteReader(CommandBehavior.CloseConnection);
cmd.Parameters.Clear();
return rdr;
}
catch {
conn.Close();
throw;
}
}

 public static object ExecuteScalar(string connectionString, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {
SqlCommand cmd = new SqlCommand();

using (SqlConnection connection = new SqlConnection(connectionString)) {
PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}
}

public static object ExecuteScalar(SqlConnection connection, CommandType cmdType, string cmdText, params SqlParameter[] commandParameters) {

SqlCommand cmd = new SqlCommand();

PrepareCommand(cmd, connection, null, cmdType, cmdText, commandParameters);
object val = cmd.ExecuteScalar();
cmd.Parameters.Clear();
return val;
}

public static void CacheParameters(string cacheKey, params SqlParameter[] commandParameters) {
parmCache[cacheKey] = commandParameters;
}
 public static SqlParameter[] GetCachedParameters(string cacheKey) {
SqlParameter[] cachedParms = (SqlParameter[])parmCache[cacheKey];

if (cachedParms == null)
return null;

SqlParameter[] clonedParms = new SqlParameter[cachedParms.Length];

for (int i = 0, j = cachedParms.Length; i < j; i++)
clonedParms[i] = (SqlParameter)((ICloneable)cachedParms[i]).Clone();

return clonedParms;
}
 private static void PrepareCommand(SqlCommand cmd, SqlConnection conn, SqlTransaction trans, CommandType cmdType, string cmdText, SqlParameter[] cmdParms) {

if (conn.State != ConnectionState.Open)
conn.Open();

cmd.Connection = conn;
cmd.CommandText = cmdText;

if (trans != null)
cmd.Transaction = trans;

cmd.CommandType = cmdType;

if (cmdParms != null) {
foreach (SqlParameter parm in cmdParms)
cmd.Parameters.Add(parm);
}
}
}