Data Filtering

ReoGrid hides rows by running a filter over a data range. You can use the built‑in column filter UI, rule‑based conditional filters, or your own filter logic wired to any GUI you like.

Filter entry points

• Auto filter UI – Excel‑style drop‑downs that collect unique values per column. See Built‑in Auto Filter.
• Conditional filters – Rule objects (ConditionalDataFilter + FilterCondition) evaluated against a ColumnBasedDataSource. See Conditional Filters.
• Custom filters – Implement RowBasedDataFilter<IRowDataRecord> (or use Func<int, bool>) and call Worksheet.DoFilter(range, filter) yourself.

Minimal examples

Using a predicate

var sheet = grid.CurrentWorksheet;
var range = sheet.UsedRange;
sheet.DoFilter(range, rowIndex =>
{
    var value = sheet[rowIndex, 2];            // third column
    return value is double d && d >= 1000;     // keep rows with value >= 1000
});

Using a data filter

var condition = new ConditionalDataFilter();
condition.Conditions.Add(new FilterCondition("price", ConditionOperator.GreaterThan, 1000));
condition.OnApply += (s, e) => sheet.DoFilter("A1:D200", condition);
condition.Apply(); // triggers DoFilter

Combining filters

Use MultipleDataFilter when you want several filters to be true at once (for example, conditional rules plus free‑text search):

var condition = new ConditionalDataFilter();
var search = new TextSearchDataFilter();
var filters = new MultipleDataFilter();
filters.Filters.Add(condition);
filters.Filters.Add(search);

condition.OnApply += (s, e) => sheet.DoFilter("A1:F300", filters);
search.OnApply += (s, e) => sheet.DoFilter("A1:F300", filters);

On-screen vs. data-driven filtering

• On-screen filter (UI-driven): The built-in auto filter and conditional filters hide rows that already exist on the sheet. They work against the range currently loaded in the worksheet.
• Data-driven filter: If your data source supports filtering/querying, filter there first (e.g., database query, in-memory LINQ) and then bind the filtered ColumnBasedDataSource to the sheet. ReoGrid will display only the filtered records, and any additional on-screen filters apply on top of that.

Build your own filter UI

1. Render controls (panel, list, checkboxes, etc.) wherever you want—often in a header drop‑down.
2. When the user changes selections, update your filter object(s) and call Apply(); handle OnApply to call Worksheet.DoFilter(range, filter).
3. For header drop‑downs, derive from DropdownHeaderCell and attach your control as the drop‑down content, then install the header body on the column header.

More details

• Built‑in UI creation and usage: Built‑in Auto Filter
• Rule syntax, operators, and data parsing: Conditional Filters