Casual Ideas for Software Development

My solution is not the first; however, I think, it is rather universal and very short - less than 20 lines of the code. The algorithm is simple: to bypass all the rows, starting from the second at the bottom, to the top. If a cell value is the same as a value in the previous (lower) row, then increase RowSpan and make the lower cell invisible, and so forth. The code that merges the cells is very short: public class GridDecorator { public static void MergeRows(GridView gridView) { for (int rowIndex = gridView.Rows.Count - 2; rowIndex >= 0; rowIndex--) { GridViewRow row = gridView.Rows[rowIndex]; GridViewRow previousRow = gridView.Rows[rowIndex + 1]; for (int i = 0; i < row.Cells.Count; i++) { if (row.Cells[i].Text == previousRow.Cells[i].Text) { row.Cells[i].RowSpan = previousRow.Cells[i].RowSpan < 2 ? 2 : ...

If you are using checkboxes in GridView in order to select a few rows, then, no doubt, you have been faced with the task how to select/deselect all checkboxes in a selected column at a time. Usually it is solved by addition of special buttons somewhere or addition a checkbox in the GridView's column header. I want to dwell on the second variant. In order to refrain from repetition of code all of required functionality can be hidden inside of a special control. This control is inherited from the CheckBox and have only one method overriden (OnLoad). Inside the method a script is registered, this script allows to select/deselect all checkboxes in a GridView's column if a checkbox in the GridView's header is clicked. Besides, the script tracks situation when all checkboxes in rows are selected one by one and selects the checkbox in the column's header. public class GridViewCheckBox : CheckBox { protected override void OnLoad(EventArgs e) { GridViewRow parentRow = th...

PagerTemplate allows to create any configuration of pager but it also requires custom paging to be implemented. Sometimes built-in paging completely meet all needs but a little modification is reduired, for example, ability to change page size. That can be done within RowCreated event handler. <asp:GridView ID="GridView1" runat=server AllowPaging="True" OnRowCreated="GridView1_RowCreated" ... Code behind: protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.Pager) { DropDownList ddl = new DropDownList(); //adds variants of pager size ddl.Items.Add("5"); ddl.Items.Add("10"); ddl.AutoPostBack = true; //selects item due to the GridView current page size ListItem li = ddl.Items.FindByText(GridView1.PageSize.ToString()); if (li != null) ddl.SelectedIndex = ddl.Items.IndexOf(li); ddl.Se...

As necessity to show header columns in a few rows occurs fairly often it would be good to have such functionality in the GridView/DataGrid control as an in-built feature. But meanwhile everyone solves this problem in his own way. The described below variant of the merging implementation is based on irwansyah 's idea to use the SetRenderMethodDelegate method for custom rendering of grid columns header. I guess this approach can be simplified in order to get more compact and handy code for reuse. The code overview As it may be required to merge a few groups of columns - for example, 1,2 and 4,5,6 - we need a class to store common information about all united columns. [Serializable] private class MergedColumnsInfo { // indexes of merged columns public List<int> MergedColumns = new List<int>(); // key-value pairs: key = the first column index, value = number of the merged columns public Hashtable StartColumns = new Hashtable(); // key-value pairs: ke...

For unknown reason the GridView pager in Numeric and NumericFirstLast modes does not take into consideration values of the PreviousPageText and NextPageText properties from the pager settings. Instead an ellipsis is shown. Of course, you may say that the buttons with the ellipsis implement a bit different functionality. Yes, they do. But the problem leaves - text on these buttons is not customizable. Sometimes it becomes problematic especially if your customer is too pernickety. To solve this flaw you can use next approach: GridView1.RowDataBound+=new GridViewRowEventHandler(GridView1_RowDataBound); protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e) { if (e.Row.RowType == DataControlRowType.Pager) { Table pagerTable = (Table)e.Row.Cells[0].Controls[0]; TableRow pagerRow = pagerTable.Rows[0]; PagerSettings pagerSettings = ((GridView)sender).PagerSettings; int cellsCount = pagerRow.Cells.Count; if (pagerSettings.Mo...

Fairly often, such a data presentation model is used: an array of objects is bound to a GridView control with predefined columns. This model was popularized by the DotNetNuke web framework and has the advantage of working with the business objects instead of nameless rows of a data table. A classic example: <asp:GridView id="gv" runat="server" AutoGenerateColumns="False" ... <Columns> <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" /> ... </Columns> </asp:GridView> and elsewhere in Page_Load: if (!IsPostBack) { gv.DataSource = someArray; gv.DataBind(); } A pretty good model, in my opinion. But, the GridView control does not have built-in ability for sorting and paging if it is bound to an array of objects. Let's implement it. The code overview I inherit my control from the GridView control and override the OnInit method in order to add two...