Expression Class

An expression assigned to a QueryParameter, EFParameter, or Parameter.

Namespace: DevExpress.DataAccess

Assembly: DevExpress.DataAccess.v18.1.dll

Declaration

C#

[TypeConverter(typeof(Expression.ExpressionTypeConverter))]
public class Expression :
    IFormattable

VB.NET

<TypeConverter(GetType(Expression.ExpressionTypeConverter))>
Public Class Expression
    Implements IFormattable

Related API Members

The following members accept/return Expression objects:

• IParameterViewModel.Expression

Remarks

If required, the expression can reference report parameters or dashboard parameters.

Related GitHub Examples

The following code snippets (auto-collected from DevExpress Examples) contain references to the Expression class.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

how-to-pass-a-dashboard-parameter-to-a-custom-sql-query-in-code-e5120/CS/Dashboard_ParametersAndCustomSQL/Form1.cs#L23

CustomSqlQuery salesPersonQuery = (CustomSqlQuery)dataSource.Queries[0];
salesPersonQuery.Parameters.Add(new QueryParameter("startDate", typeof(Expression),
    new Expression("[Parameters.yearParameter] + '/01/01'")));

how-to-create-data-access-library-data-sources-at-runtime-t424210/CS/SqlDataSourceSnippets/Code.cs#L52

Name = "catID",
Type = typeof(DevExpress.DataAccess.Expression),
Value = new DevExpress.DataAccess.Expression("[Parameters.catID]", typeof(System.Int32))

Reporting_how-to-dynamically-pass-xtrareport-parameters-into-the-underlying-sqldatasource-to-t158360/CS/WindowsFormsApplication1/Form1.cs#L25

queryParameter1.Name = "p1";
queryParameter1.Type = typeof(DevExpress.DataAccess.Expression);
queryParameter1.Value = new DevExpress.DataAccess.Expression("[Parameters.CatID]");

Reporting_how-to-programmatically-filter-report-data-at-the-data-source-level-using-query-t203059/CS/QueryParametersRuntime/XtraReport1.cs#L35

Name = "catID",
Type = typeof(Expression),
Value = new Expression("[Parameters.catID]", typeof(System.Int32))

VB.NET

how-to-pass-a-dashboard-parameter-to-a-custom-sql-query-in-code-e5120/VB/Dashboard_ParametersAndCustomSQL/Form1.vb#L27

    CType(dataSource.Queries(0), CustomSqlQuery)
salesPersonQuery.Parameters.Add(New QueryParameter("startDate", GetType(Expression), _
                                New Expression("[Parameters.yearParameter] + '/01/01'")))

Reporting_how-to-dynamically-pass-xtrareport-parameters-into-the-underlying-sqldatasource-to-t158360/VB/WindowsFormsApplication1/Form1.vb#L23

queryParameter1.Name = "p1"
queryParameter1.Type = GetType(DevExpress.DataAccess.Expression)
queryParameter1.Value = New DevExpress.DataAccess.Expression("[Parameters.CatID]")

Reporting_how-to-programmatically-filter-report-data-at-the-data-source-level-using-query-t203059/VB/QueryParametersRuntime/XtraReport1.vb#L33

.Name = "catID", _
.Type = GetType(Expression), _
.Value = New Expression("[Parameters.catID]", GetType(System.Int32)) _

how-to-create-data-access-library-data-sources-at-runtime-t424210/VB/SqlDataSourceSnippets/Code.vb#L35

Private Sub QueryParameterInitialization(ByVal query As SelectQuery)
    Dim parameter As New QueryParameter() With {.Name = "catID", .Type = GetType(DevExpress.DataAccess.Expression), .Value = New DevExpress.DataAccess.Expression("[Parameters.catID]", GetType(System.Int32))}
    query.Parameters.Add(parameter)

Inheritance

Object

Expression