IDataStore.Filter(string format) Method
.NET Standard 2.x
Filters rows by the current filter criteria. Rows that do not meet the filter criteria are moved to the filter buffer. The filter criteria can be re-set using the format
parameter.
Namespace: DWNet.Data
Assembly: DWNet.Data.dll
Syntax
public bool Filter(string format);
Parameters
format
System.String
(Optional) A string whose value is a Boolean
expression that you want to use as the filter criteria. The expression includes column names or numbers. A column number must be preceded by a pound sign (#).
Returns
System.Boolean
Returns true
if it succeeds.
Remarks
When the format
parameter is not specified, the Filter
method uses the current filter criteria for the DataStore. To change the filter criteria, use the SetFilter
method. If you do not call SetFilter
to assign or change criteria before calling the Filter
method, the DataStore will default to use the criteria in the DataWindow object
definition.
When the Retrieve
method retrieves data for the DataStore, it applies the filter that was defined for the DataWindow object
, if any. You only need to call Filter
after you change the filter criteria with SetFilter
or if the data has changed because of processing or user input.
Examples
The following code example demonstrates how to use the Filter
method to filter the data and reset the filter criteria.
using Appeon.ApiDoc.Models;
using DWNet.Data;
using System;
namespace Appeon.ApiDoc.IDataStoreExamples
{
public class FilterExample
{
private readonly SchoolContext _context;
public FilterExample(SchoolContext dataContext)
{
// Sets the data context
_context = dataContext;
}
public void Example1()
{
// Instantiates a DataStore object with datawindow: d_department.
var datastore = new DataStore("d_department", _context);
datastore.Retrieve();
// Sets the filter criteria to 'departmentid < 3'.
datastore.Filter("departmentid < 3");
Console.WriteLine("datastore.RowCount: {0}",
datastore.RowCount);
// Resets the filter criteria via the format argument.
datastore.Filter("departmentid < 5");
// There are 3 records that meet the criteria
Console.WriteLine("datastore.RowCount: {0}",
datastore.RowCount);
/*This code produces the following output:
datastore.RowCount: 2
datastore.RowCount: 3
*/
}
}
}
Example Refer To
Model Class: D_Department
DataWindow File: d_department
Applies to
.NET Standard
2.x