SqlDataSource.FillAsync(IEnumerable<IParameter>) Method
Populates the SqlDataSource in an asynchronous manner and passes external parameters to the data source.
Namespace: DevExpress.DataAccess.Sql
Assembly: DevExpress.DataAccess.v20.2.dll
NuGet Packages: DevExpress.DataAccess, DevExpress.WindowsDesktop.DataAccess
Declaration
Parameters
| Name | Type | Description |
|---|---|---|
| sourceParameters | IEnumerable<IParameter> | External parameters passed to the data source. |
Returns
| Type | Description |
|---|---|
| Task | A task that populates the data source. |
Remarks
Use this method to populate an SQL data source in an individual task asynchronously. Unlike the Fill() method call, FillAsync does not lock other actions performed concurrently. For instance, the user interface remains operational while the data source is populated.
Call the FillAsync method with the await operator.
The sourceParameters parameter passes a collection of external parameters to the data source. For instance, you can pass report parameters from a reporting application and use report parameter values to filter data.
All queries are validated one by one. If any validation errors occur, an AggregateException is thrown with these errors. Use the exception’s InnerExceptions property to access a collection of QueryExecutionException objects (use their InnerException property to access an actual ValidationException).
If the validation succeeds, all queries are executed one by one. If any errors occur, an AggregateException is thrown with these errors. Use the exception’s InnerExceptions property to access a collection of QueryExecutionException objects (use their InnerException property to access an actual DevExpress.DataAccess.Native.Sql.SqlExecutionException).
To validate and execute only specific queries, use a FillAsync method overload that accepts the queriesToFill parameter.
Example
The code sample below creates an SqlDataSource, binds the data source query’s OrderIDs parameter to the OrderIDsParameter report parameter, and populates the data source in an asynchronous manner.
using System.Threading;
using System.Threading.Tasks;
using DevExpress.DataAccess;
using DevExpress.DataAccess.Sql;
using DevExpress.DataAccess.ConnectionParameters;
// ...
// Create and configure an SQL data source.
Access97ConnectionParameters connectionParameters = new Access97ConnectionParameters(".\\Data\\nwind.mdb", "", "");
DevExpress.DataAccess.Sql.SqlDataSource dataSource = new DevExpress.DataAccess.Sql.SqlDataSource(connectionParameters);
// The "queryInvoices" query uses the "OrderIDs" query parameter that is bound to the "OrderIDsParameter" report parameter.
CustomSqlQuery queryInvoices = new CustomSqlQuery();
queryInvoices.Name = "queryInvoices";
queryInvoices.Sql = "SELECT OrderID, OrderDate, ShipName, sum(ExtendedPrice) as Total FROM Invoices WHERE OrderID in (?OrderIDs) GROUP BY OrderID,OrderDate,ShipName";
queryInvoices.Parameters.Add(new QueryParameter("OrderIDs", typeof(System.Int32), "?OrderIDsParameter"));
dataSource.Queries.Add(queryInvoices);
report.DataSource = dataSource;
report.DataMember = "queryInvoices";
// Populate the data source.
await dataSource.FillAsync(report.Parameters);
report.DataSource = dataSource;