C# 4 and .NET 4

standard Controls and Components ❘ 1133
figure 39-6
The filter not only applies to the visible rows but also to the state of the columns within those rows. This is
evident when choosing the ModifiedOriginal or ModifiedCurrent selections. These states are based on
the DataRowVersion enumeration. For example, when the user has updated a column in the row, the
row will be displayed when either ModifiedOriginal or ModifiedCurrent is chosen; however, the actual
value will be either the Original value selected from the database (if ModifiedOriginal is chosen) or the
current value in the DataColumn (if ModifiedCurrent is chosen).
Sorting Rows
Apart from filtering data, you might also have to sort the data
within a DataView. To sort data in ascending or descending order,
simply click the column header in the DataGridView control (see
Figure 39-7). The only trouble is that the control can sort by only
one column, whereas the underlying DataView control can sort by
multiple columns.
When a column is sorted, either by clicking the header (as shown on the SupplierId column) or in code,
the DataGrid displays an arrow bitmap to indicate which column the sort has been applied to.
To set the sort order on a column programmatically, use the Sort property of the DataView:
dataView.Sort = "ProductName";
dataView.Sort = "ProductName ASC, ProductID DESC";
figure 39-7
The first line sorts the data based on the ProductName column, as shown in Figure 39-7. The second line
sorts the data in ascending order, based on the ProductName column, then in descending order of ProductID.
The DataView supports both ascending (default) and descending sort orders on columns. If more than one
column is sorted in code in the DataView, the DataGridView will cease to display any sort arrows.
Each column in the grid can be strongly typed, so its sort order is not based on the string representation of
the column but instead is based on the data within that column. The upshot is that if there is a date column
in the DataGrid, the user can sort numerically on the date rather than on the date string representation.
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