Grid View for ASP.NET Web Forms - How to apply custom function filter criteria operators

This example demonstrates how to use a CriteriaPatchBase class descendant to apply a custom function criteria operator.

Overview

Assign a custom function operator to the grid's FilterExpression property. For the auto filter row, handle the grid's server-side ProcessColumnAutoFilter event as follows:

protected void Grid_ProcessColumnAutoFilter(object sender, DevExpress.Web.ASPxGridViewAutoFilterEventArgs e) {
    var grid = (ASPxGridView)sender;
    if(e.Column.FieldName == SpecialFilterColumnFieldName && e.Kind == GridViewAutoFilterEventKind.CreateCriteria) {
        grid.FilterExpression = UpdateGridFilterExpression(grid, e);
        e.Criteria = null;
    }
}

Handle the grid's server-side AutoFilterCellEditorInitialize event to assign the custom criteria operator value to the filter editor.

protected void Grid_AutoFilterCellEditorInitialize(object sender, ASPxGridViewEditorEventArgs e) {
    var grid = (ASPxGridView)sender;
    if(e.Column.FieldName == SpecialFilterColumnFieldName) {
        var gridCriteria = CriteriaOperator.Parse(grid.FilterExpression);
        e.Editor.Value = CriteriaVisitor.GetCustomFunctionOperatorValue(gridCriteria, e.Column.FieldName);
    }
}

Files to Review

• CriteriaPatcherBase.cs (VB: CriteriaPatcherBase.vb)
• CriteriaVisitor.cs (VB: CriteriaVisitor.vb)
• MyCustomFunctionOperator.cs (VB: MyCustomFunctionOperator.vb)
• Default.aspx (VB: Default.aspx)
• Default.aspx.cs (VB: Default.aspx.vb)

Documentation

• The base implementation of the IClientCriteriaVisitor interface for the CriteriaOperator expression patcher

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