Conversione DataTable al tipo stringa
-
10-10-2019 - |
Domanda
Ho una funzione come questa ??p>
public DataTable GetAllPrimaryKeyTables(string localServer, string userName, string password, string selectedDatabase)
{
// Create the datatable
DataTable dtListOfPrimaryKeyTables = new DataTable("tableNames");
SqlConnectionStringBuilder objConnectionString = new SqlConnectionStringBuilder();
objConnectionString.DataSource = localServer; ;
objConnectionString.UserID = userName;
objConnectionString.Password = password;
objConnectionString.InitialCatalog = selectedDatabase;
// Query to select primary key tables.
string selectPrimaryKeyTables = @"SELECT
TABLE_NAME
AS
TABLES
FROM
INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE
CONSTRAINT_TYPE = 'PRIMARY KEY'
AND
TABLE_NAME <> 'dtProperties'
ORDER BY
TABLE_NAME";
// put your SqlConnection and SqlCommand into using blocks!
using(SqlConnection sConnection = new SqlConnection(objConnectionString.ConnectionString))
using(SqlCommand sCommand = new SqlCommand(selectPrimaryKeyTables, sConnection))
{
try
{
// Create the dataadapter object
SqlDataAdapter sDataAdapter = new SqlDataAdapter(selectPrimaryKeyTables, sConnection);
// Fill the datatable - no need to open the connection, the SqlDataAdapter will do that all by itself
// (and also close it again after it is done)
sDataAdapter.Fill(dtListOfPrimaryKeyTables);
}
catch(Exception ex)
{
//All the exceptions are handled and written in the EventLog.
EventLog log = new EventLog("Application");
log.Source = "MFDBAnalyser";
log.WriteEntry(ex.Message);
}
}
// return the data table to the caller
return dtListOfPrimaryKeyTables;
}
Poi ho voluto ottenere il tipo restituito come stringa e non come DataTable così ho fatto questo ..
public string GetAllPrimaryKeyTables(string ConnectionString)
{
string result = string.Empty;
// Query to select primary key tables.
string selectPrimaryKeyTables = @"SELECT
TABLE_NAME
AS
TABLES
FROM
INFORMATION_SCHEMA.TABLE_CONSTRAINTS
WHERE
CONSTRAINT_TYPE = 'PRIMARY KEY'
AND
TABLE_NAME <> 'dtProperties'
ORDER BY
TABLE_NAME";
// put your SqlConnection and SqlCommand into using blocks!
using(SqlConnection sConnection = new SqlConnection(ConnectionString))
using(SqlCommand sCommand = new SqlCommand(selectPrimaryKeyTables, sConnection))
{
try
{
// Create the dataadapter object
SqlDataAdapter sDataAdapter = new SqlDataAdapter(selectPrimaryKeyTables, sConnection);
DataTable dtListOfPrimaryKeyTables = new DataTable("tableNames");
// Fill the datatable - no need to open the connection, the SqlDataAdapter will do that all by itself
// (and also close it again after it is done)
sDataAdapter.Fill(dtListOfPrimaryKeyTables);
using(StringWriter sw = new StringWriter())
{
dtListOfPrimaryKeyTables.WriteXml(sw);
result = sw.ToString();
}
}
catch(Exception ex)
{
//All the exceptions are handled and written in the EventLog.
EventLog log = new EventLog("Application");
log.Source = "MFDBAnalyser";
log.WriteEntry(ex.Message);
}
}
// return the data table to the caller
return result;
}
Ma questo non è tornando la stringa, che si deve ...
Mi può indirizzare al punto che le modifiche richieste.
Soluzione
Al posto di un StringWriter
, utilizzare un StringBuilder
, quindi è possibile utilizzare i metodi Write
e WriteLine
.
Altri suggerimenti
Se si desidera lista una virgola separati, si potrebbe usare qualcosa come qui di seguito.
private string GetList(ds)
{
var result = string.Empty;
for(int i = 0; i < ds.Rows.Count; i++)
{
result += ds.Row[i][0] + ",";
}
result = result.Trim(',');
return result;
}
Spero che questo aiuti.
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