Added a CSV editor Scenario and an article introducing table view and how to use it

UICatalog/Scenarios/CsvEditor.cs

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+using System;
+using System.Collections.Generic;
+using System.Data;
+using Terminal.Gui;
+using System.Linq;
+using System.Globalization;
+using System.IO;
+using System.Text;
+
+namespace UICatalog.Scenarios {
+
+	[ScenarioMetadata (Name: "Csv Editor", Description: "Open and edit simple CSV files")]
+	[ScenarioCategory ("Controls")]
+	[ScenarioCategory ("Dialogs")]
+	[ScenarioCategory ("Text")]
+	[ScenarioCategory ("Dialogs")]
+	[ScenarioCategory ("TopLevel")]
+	public class CsvEditor : Scenario 
+	{
+		TableView tableView;
+		private string currentFile;
+
+		public override void Setup ()
+		{
+			Win.Title = this.GetName();
+			Win.Y = 1; // menu
+			Win.Height = Dim.Fill (1); // status bar
+			Top.LayoutSubviews ();
+
+			this.tableView = new TableView () {
+				X = 0,
+				Y = 0,
+				Width = Dim.Fill (),
+				Height = Dim.Fill (1),
+			};
+
+			var menu = new MenuBar (new MenuBarItem [] {
+				new MenuBarItem ("_File", new MenuItem [] {
+					new MenuItem ("_Open CSV", "", () => Open()),
+					new MenuItem ("_Save", "", () => Save()),
+					new MenuItem ("_Quit", "", () => Quit()),
+				}),
+				new MenuBarItem ("_Edit", new MenuItem [] {
+					new MenuItem ("_Rename Column", "", () => RenameColumn()),
+				}),
+				new MenuBarItem ("_Insert", new MenuItem [] {
+					new MenuItem ("_New Column", "", () => AddColumn()),
+					new MenuItem ("_New Row", "", () => AddRow()),
+				})
+			});
+			Top.Add (menu);
+
+			var statusBar = new StatusBar (new StatusItem [] {
+				new StatusItem(Key.CtrlMask | Key.O, "~^O~ Open", () => Open()),
+				new StatusItem(Key.CtrlMask | Key.S, "~^S~ Save", () => Save()),
+				new StatusItem(Key.CtrlMask | Key.Q, "~^Q~ Quit", () => Quit()),
+			});
+			Top.Add (statusBar);
+
+			Win.Add (tableView);
+
+			var selectedCellLabel = new Label(){
+				X = 0,
+				Y = Pos.Bottom(tableView),
+				Text = "0,0",
+				Width = Dim.Fill(),
+				TextAlignment = TextAlignment.Right
+				
+			};
+
+			Win.Add(selectedCellLabel);
+
+			tableView.SelectedCellChanged += (e)=>{selectedCellLabel.Text = $"{tableView.SelectedRow},{tableView.SelectedColumn}";};
+			tableView.CellActivated += EditCurrentCell;
+			tableView.KeyPress += TableViewKeyPress;
+
+			SetupScrollBar();
+		}
+
+		private void RenameColumn ()
+		{
+			if(NoTableLoaded()) {
+				return;
+			}
+
+			var currentCol = tableView.Table.Columns[tableView.SelectedColumn];
+
+			if(GetText("Rename Column","Name:",currentCol.ColumnName,out string newName)) {
+				currentCol.ColumnName = newName;
+				tableView.Update();
+			}
+
+
+		}
+
+		private bool NoTableLoaded ()
+		{
+			if(tableView.Table == null) {
+				MessageBox.ErrorQuery("No Table Loaded","No table has currently be opened","Ok");
+				return true;
+			}
+
+			return false;
+		}
+
+		private void AddRow ()
+		{
+			if(NoTableLoaded()) {
+				return;
+			}
+
+			tableView.Table.Rows.Add();
+			tableView.Update();
+		}
+
+		private void AddColumn ()
+		{
+			if(NoTableLoaded()) {
+				return;
+			}
+
+			if(GetText("Enter column name","Name:","",out string colName)) {
+				tableView.Table.Columns.Add(new DataColumn(colName));
+				tableView.Update();
+			}
+				
+		}
+
+		private void Save()
+		{
+			if(tableView.Table == null || string.IsNullOrWhiteSpace(currentFile)) {
+				MessageBox.ErrorQuery("No file loaded","No file is currently loaded","Ok");
+				return;
+			}
+
+			var sb = new StringBuilder();
+
+			sb.AppendLine(string.Join(",",tableView.Table.Columns.Cast<DataColumn>().Select(c=>c.ColumnName)));
+
+			foreach(DataRow row in tableView.Table.Rows) {
+				sb.AppendLine(string.Join(",",row.ItemArray));
+			}
+			
+			File.WriteAllText(currentFile,sb.ToString());
+		}
+
+		private void Open()
+		{
+			var ofd = new FileDialog("Select File","Open","File","Select a CSV file to open (does not support newlines, escaping etc)");
+			ofd.AllowedFileTypes = new string[]{".csv" };
+
+			Application.Run(ofd);
+			
+			if(!string.IsNullOrWhiteSpace(ofd.FilePath?.ToString()))
+			{
+				Open(ofd.FilePath.ToString());
+			}
+		}
+		
+		private void Open(string filename)
+		{
+			
+			int lineNumber = 0;
+			currentFile = null;
+
+			try {
+				var dt = new DataTable();
+				var lines = File.ReadAllLines(filename);
+			
+				foreach(var h in lines[0].Split(',')){
+					dt.Columns.Add(h);
+				}
+				
+
+				foreach(var line in lines.Skip(1)) {
+					lineNumber++;
+					dt.Rows.Add(line.Split(','));
+				}
+				
+				tableView.Table = dt;
+				
+				// Only set the current filename if we succesfully loaded the entire file
+				currentFile = filename;
+			}
+			catch(Exception ex) {
+				MessageBox.ErrorQuery("Open Failed",$"Error on line {lineNumber}{Environment.NewLine}{ex.Message}","Ok");
+			}
+		}
+		private void SetupScrollBar ()
+		{
+			var _scrollBar = new ScrollBarView (tableView, true);
+
+			_scrollBar.ChangedPosition += () => {
+				tableView.RowOffset = _scrollBar.Position;
+				if (tableView.RowOffset != _scrollBar.Position) {
+					_scrollBar.Position = tableView.RowOffset;
+				}
+				tableView.SetNeedsDisplay ();
+			};
+			/*
+			_scrollBar.OtherScrollBarView.ChangedPosition += () => {
+				_listView.LeftItem = _scrollBar.OtherScrollBarView.Position;
+				if (_listView.LeftItem != _scrollBar.OtherScrollBarView.Position) {
+					_scrollBar.OtherScrollBarView.Position = _listView.LeftItem;
+				}
+				_listView.SetNeedsDisplay ();
+			};*/
+
+			tableView.DrawContent += (e) => {
+				_scrollBar.Size = tableView.Table?.Rows?.Count ??0;
+				_scrollBar.Position = tableView.RowOffset;
+			//	_scrollBar.OtherScrollBarView.Size = _listView.Maxlength - 1;
+			//	_scrollBar.OtherScrollBarView.Position = _listView.LeftItem;
+				_scrollBar.Refresh ();
+			};
+		
+		}
+
+		private void TableViewKeyPress (View.KeyEventEventArgs e)
+		{
+			if(e.KeyEvent.Key == Key.DeleteChar){
+
+				if(tableView.FullRowSelect)
+				{
+					// Delete button deletes all rows when in full row mode
+					foreach(int toRemove in tableView.GetAllSelectedCells().Select(p=>p.Y).Distinct().OrderByDescending(i=>i))
+						tableView.Table.Rows.RemoveAt(toRemove);
+				}
+				else{
+
+					// otherwise set all selected cells to null
+					foreach(var pt in tableView.GetAllSelectedCells())
+					{
+						tableView.Table.Rows[pt.Y][pt.X] = DBNull.Value;
+					}
+				}
+
+				tableView.Update();
+				e.Handled = true;
+			}
+		}
+
+		private void ClearColumnStyles ()
+		{
+			tableView.Style.ColumnStyles.Clear();
+			tableView.Update();
+		}
+			
+
+		private void CloseExample ()
+		{
+			tableView.Table = null;
+		}
+
+		private void Quit ()
+		{
+			Application.RequestStop ();
+		}
+
+		private void OpenExample (bool big)
+		{
+			tableView.Table = BuildDemoDataTable(big ? 30 : 5, big ? 1000 : 5);
+			SetDemoTableStyles();
+		}
+
+		private void SetDemoTableStyles ()
+		{
+			var alignMid = new ColumnStyle() {
+				Alignment = TextAlignment.Centered
+			};
+			var alignRight = new ColumnStyle() {
+				Alignment = TextAlignment.Right
+			};
+
+			var dateFormatStyle = new ColumnStyle() {
+				Alignment = TextAlignment.Right,
+				RepresentationGetter = (v)=> v is DateTime d ? d.ToString("yyyy-MM-dd"):v.ToString()
+			};
+
+			var negativeRight = new ColumnStyle() {
+				
+				Format = "0.##",
+				MinWidth = 10,
+				AlignmentGetter = (v)=>v is double d ? 
+								// align negative values right
+								d < 0 ? TextAlignment.Right : 
+								// align positive values left
+								TextAlignment.Left:
+								// not a double
+								TextAlignment.Left
+			};
+			
+			tableView.Style.ColumnStyles.Add(tableView.Table.Columns["DateCol"],dateFormatStyle);
+			tableView.Style.ColumnStyles.Add(tableView.Table.Columns["DoubleCol"],negativeRight);
+			tableView.Style.ColumnStyles.Add(tableView.Table.Columns["NullsCol"],alignMid);
+			tableView.Style.ColumnStyles.Add(tableView.Table.Columns["IntCol"],alignRight);
+			
+			tableView.Update();
+		}
+
+		private void OpenSimple (bool big)
+		{
+			tableView.Table = BuildSimpleDataTable(big ? 30 : 5, big ? 1000 : 5);
+		}
+		private bool GetText(string title, string label, string initialText, out string enteredText)
+		{
+			bool okPressed = false;
+
+			var ok = new Button ("Ok", is_default: true);
+			ok.Clicked += () => { okPressed = true; Application.RequestStop (); };
+			var cancel = new Button ("Cancel");
+			cancel.Clicked += () => { Application.RequestStop (); };
+			var d = new Dialog (title, 60, 20, ok, cancel);
+
+			var lbl = new Label() {
+				X = 0,
+				Y = 1,
+				Text = label
+			};
+
+			var tf = new TextField()
+				{
+					Text = initialText,
+					X = 0,
+					Y = 2,
+					Width = Dim.Fill()
+				};
+			
+			d.Add (lbl,tf);
+			tf.SetFocus();
+
+			Application.Run (d);
+
+			enteredText = okPressed? tf.Text.ToString() : null;
+			return okPressed;
+		}
+		private void EditCurrentCell (CellActivatedEventArgs e)
+		{
+			if(e.Table == null)
+				return;
+
+			var oldValue = e.Table.Rows[e.Row][e.Col].ToString();
+
+			if(GetText("Enter new value",e.Table.Columns[e.Col].ColumnName,oldValue, out string newText)) {
+				try {
+					e.Table.Rows[e.Row][e.Col] = string.IsNullOrWhiteSpace(newText) ? DBNull.Value : (object)newText;
+				}
+				catch(Exception ex) {
+					MessageBox.ErrorQuery(60,20,"Failed to set text", ex.Message,"Ok");
+				}
+				
+				tableView.Update();
+			}
+		}
+
+		/// <summary>
+		/// Generates a new demo <see cref="DataTable"/> with the given number of <paramref name="cols"/> (min 5) and <paramref name="rows"/>
+		/// </summary>
+		/// <param name="cols"></param>
+		/// <param name="rows"></param>
+		/// <returns></returns>
+		public static DataTable BuildDemoDataTable(int cols, int rows)
+		{
+			var dt = new DataTable();
+
+			int explicitCols = 6;
+			dt.Columns.Add(new DataColumn("StrCol",typeof(string)));
+			dt.Columns.Add(new DataColumn("DateCol",typeof(DateTime)));
+			dt.Columns.Add(new DataColumn("IntCol",typeof(int)));
+			dt.Columns.Add(new DataColumn("DoubleCol",typeof(double)));
+			dt.Columns.Add(new DataColumn("NullsCol",typeof(string)));
+			dt.Columns.Add(new DataColumn("Unicode",typeof(string)));
+
+			for(int i=0;i< cols -explicitCols; i++) {
+				dt.Columns.Add("Column" + (i+explicitCols));
+			}
+			
+			var r = new Random(100);
+
+			for(int i=0;i< rows;i++) {
+				
+				List<object> row = new List<object>(){ 
+					"Some long text that is super cool",
+					new DateTime(2000+i,12,25),
+					r.Next(i),
+					(r.NextDouble()*i)-0.5 /*add some negatives to demo styles*/,
+					DBNull.Value,
+					"Les Mise" + Char.ConvertFromUtf32(Int32.Parse("0301", NumberStyles.HexNumber)) + "rables"
+				};
+				
+				for(int j=0;j< cols -explicitCols; j++) {
+					row.Add("SomeValue" + r.Next(100));
+				}
+
+				dt.Rows.Add(row.ToArray());
+			}
+
+			return dt;
+		}
+
+		/// <summary>
+		/// Builds a simple table in which cell values contents are the index of the cell.  This helps testing that scrolling etc is working correctly and not skipping out any rows/columns when paging
+		/// </summary>
+		/// <param name="cols"></param>
+		/// <param name="rows"></param>
+		/// <returns></returns>
+		public static DataTable BuildSimpleDataTable(int cols, int rows)
+		{
+			var dt = new DataTable();
+
+			for(int c = 0; c < cols; c++) {
+				dt.Columns.Add("Col"+c);
+			}
+				
+			for(int r = 0; r < rows; r++) {
+				var newRow = dt.NewRow();
+
+				for(int c = 0; c < cols; c++) {
+					newRow[c] = $"R{r}C{c}";
+				}
+
+				dt.Rows.Add(newRow);
+			}
+			
+			return dt;
+		}
+	}
+}

docfx/articles/tableview.md

@@ -0,0 +1,57 @@
+# Table View
+
+This control supports viewing and editing tabular data.  It provides a view of a [System.DataTable](https://docs.microsoft.com/en-us/dotnet/api/system.data.datatable?view=net-5.0).
+
+System.DataTable is a core class of .net standard and can be created very easily
+
+## Csv Example
+
+You can create a DataTable from a CSV file by creating a new instance and adding columns and rows as you read them.  For a robust solution however you might want to look into a CSV parser library that deals with escaping, multi line rows etc.
+
+```csharp
+var dt = new DataTable();
+var lines = File.ReadAllLines(filename);
+			
+foreach(var h in lines[0].Split(',')){
+	dt.Columns.Add(h);
+}
+				
+
+foreach(var line in lines.Skip(1)) {
+	lineNumber++;
+	dt.Rows.Add(line.Split(','));
+}
+```
+
+## Database Example
+
+All Ado.net database providers (Oracle, MySql, SqlServer etc) support reading data as DataTables for example:
+
+```csharp
+var dt = new DataTable();
+
+using(var con = new SqlConnection("Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;"))
+{
+    con.Open();
+    var cmd = new SqlCommand("select * from myTable;",con);
+    var adapter = new SqlDataAdapter(cmd);
+
+    adapter.Fill(dt);
+}
+```
+
+## Displaying the table
+
+Once you have set up your data table set it in the view:
+
+```csharp
+tableView = new TableView () {
+	X = 0,
+	Y = 0,
+	Width = 50,
+	Height = 10,
+};
+
+tableView.Table = yourDataTable;
+```
+