Added basic table viewing

Terminal.Gui/Views/TableView.cs

@@ -0,0 +1,190 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Terminal.Gui.Views {
+
+	/// <summary>
+	/// View for tabular data based on a <see cref="DataTable"/>
+	/// </summary>
+	public class TableView : View {
+
+		private int columnOffset;
+		private int rowOffset;
+
+		public DataTable Table { get; private set; }
+
+		/// <summary>
+		/// Zero indexed offset for the upper left <see cref="DataColumn"/> to display in <see cref="Table"/>.
+		/// </summary>
+		/// <remarks>This property allows very wide tables to be rendered with horizontal scrolling</remarks>
+		public int ColumnOffset {
+			get => columnOffset; 
+
+			//try to prevent this being set to an out of bounds column
+			set => columnOffset = Math.Min (Table.Columns.Count - 1, Math.Max (0, value));
+		}
+
+
+		/// <summary>
+		/// Zero indexed offset for the <see cref="DataRow"/> to display in <see cref="Table"/> on line 2 of the control (first line being headers)
+		/// </summary>
+		/// <remarks>This property allows very wide tables to be rendered with horizontal scrolling</remarks>
+		public int RowOffset { 
+			get => rowOffset; 
+			set => rowOffset = Math.Min (Table.Rows.Count - 1, Math.Max (0, value));
+			}
+
+		/// <summary>
+		/// The maximum number of characters to render in any given column.  This prevents one long column from pushing out all the others
+		/// </summary>
+		public int MaximumCellWidth {get;set;} = 100;
+
+		/// <summary>
+		/// The text representation that should be rendered for cells with the value <see cref="DBNull.Value"/>
+		/// </summary>
+		public string NullSymbol {get;set;} = "-";
+
+		/// <summary>
+		/// Initialzies a <see cref="TableView"/> class using <see cref="LayoutStyle.Computed"/> layout. 
+		/// </summary>
+		/// <param name="table">The table to display in the control</param>
+		public TableView (DataTable table) : base ()
+		{
+			this.Table = table ?? throw new ArgumentNullException (nameof (table));
+		}
+		///<inheritdoc/>
+		public override void Redraw (Rect bounds)
+		{
+			Attribute currentAttribute;
+			var current = ColorScheme.Focus;
+			Driver.SetAttribute (current);
+			Move (0, 0);
+
+			var frame = Frame;
+
+			int activeColor = ColorScheme.HotNormal;
+			int trackingColor = ColorScheme.HotFocus;
+
+			// What columns to render at what X offset in viewport
+			Dictionary<DataColumn, int> columnsToRender = CalculateViewport(bounds);
+
+			Driver.SetAttribute (ColorScheme.HotNormal);
+
+			// Render the headers
+			foreach(var kvp in columnsToRender) {
+				
+				Move (kvp.Value,0);
+				Driver.AddStr(kvp.Key.ColumnName);
+			}
+
+			//render the cells
+			for (int line = 1; line < frame.Height; line++) {
+				
+				//work out what Row to render
+				var rowToRender = RowOffset + (line-1);
+				if(rowToRender >= Table.Rows.Count)
+					break;
+
+				foreach(var kvp in columnsToRender) {
+					Move (kvp.Value,line);
+					Driver.AddStr(GetRenderedVal(Table.Rows[rowToRender][kvp.Key]));
+				}
+			}
+
+			/*
+
+			for (int line = 1; line < frame.Height; line++) {
+				var lineRect = new Rect (0, line, frame.Width, 1);
+				if (!bounds.Contains (lineRect))
+					continue;
+
+				Move (0, line);
+				Driver.SetAttribute (ColorScheme.HotNormal);
+				Driver.AddStr ("test");
+
+				currentAttribute = ColorScheme.HotNormal;
+				SetAttribute (ColorScheme.Normal);
+			}*/
+
+			void SetAttribute (Attribute attribute)
+			{
+				if (currentAttribute != attribute) {
+					currentAttribute = attribute;
+					Driver.SetAttribute (attribute);
+				}
+			}
+
+		}
+
+		/// <summary>
+		/// Calculates which columns should be rendered given the <paramref name="bounds"/> in which to display and the <see cref="ColumnOffset"/>
+		/// </summary>
+		/// <param name="bounds"></param>
+		/// <param name="padding"></param>
+		/// <returns></returns>
+		private Dictionary<DataColumn,int> CalculateViewport(Rect bounds, int padding = 1)
+		{
+			Dictionary<DataColumn,int> toReturn = new Dictionary<DataColumn, int>();
+
+			int usedSpace = 0;
+			int availableHorizontalSpace = bounds.Width;
+			int rowsToRender = bounds.Height-1; //1 reserved for the headers row
+			
+			foreach(var col in Table.Columns.Cast<DataColumn>().Skip(ColumnOffset)) {
+				
+				toReturn.Add(col,usedSpace);
+				usedSpace += CalculateMaxRowSize(col,rowsToRender) + padding;
+
+				if(usedSpace > availableHorizontalSpace)
+					return toReturn;
+				
+			}
+			
+			return toReturn;
+		}
+
+		/// <summary>
+		/// Returns the maximum of the <paramref name="col"/> name and the maximum length of data that will be rendered starting at <see cref="RowOffset"/> and rendering <paramref name="rowsToRender"/>
+		/// </summary>
+		/// <param name="col"></param>
+		/// <param name="rowsToRender"></param>
+		/// <returns></returns>
+		private int CalculateMaxRowSize (DataColumn col, int rowsToRender)
+		{
+			int spaceRequired = col.ColumnName.Length;
+
+			for(int i = RowOffset; i<rowsToRender && i<Table.Rows.Count;i++) {
+
+				//expand required space if cell is bigger than the last biggest cell or header
+				spaceRequired = Math.Max(spaceRequired,GetRenderedVal(Table.Rows[i][col]).Length);
+			}
+
+			return spaceRequired;
+		}
+
+		/// <summary>
+		/// Returns the value that should be rendered to best represent a strongly typed <paramref name="value"/> read from <see cref="Table"/>
+		/// </summary>
+		/// <param name="value"></param>
+		/// <returns></returns>
+		private string GetRenderedVal (object value)
+		{
+			if(value == null || value == DBNull.Value) 
+			{
+				return NullSymbol;
+			}
+			
+			var representation = value.ToString();
+
+			//if it is too long to fit
+			if(representation.Length > MaximumCellWidth)
+				return representation.Substring(0,MaximumCellWidth);
+
+			return representation;
+		}
+	}
+}

UICatalog/Scenarios/TableEditor.cs

@@ -0,0 +1,78 @@
+using System;
+using System.Collections.Generic;
+using System.Data;
+using Terminal.Gui;
+using Terminal.Gui.Views;
+
+namespace UICatalog.Scenarios {
+
+	[ScenarioMetadata (Name: "TableEditor", Description: "A Terminal.Gui DataTable editor via TableView")]
+	[ScenarioCategory ("Controls")]
+	[ScenarioCategory ("Dialogs")]
+	[ScenarioCategory ("Text")]
+	[ScenarioCategory ("Dialogs")]
+	[ScenarioCategory ("TopLevel")]
+	public class TableEditor : Scenario 
+	{
+		TableView tableView;
+
+		public override void Setup ()
+		{
+			var dt = BuildDemoDataTable(30,1000);
+
+			Win.Title = this.GetName() + "-" + dt.TableName ?? "Untitled";
+			Win.Y = 1; // menu
+			Win.Height = Dim.Fill (1); // status bar
+			Top.LayoutSubviews ();
+
+			this.tableView = new TableView (dt) {
+				X = 0,
+				Y = 0,
+				Width = Dim.Fill (),
+				Height = Dim.Fill (),
+			};
+			tableView.CanFocus = true;
+			Win.Add (tableView);
+		}
+
+		/// <summary>
+		/// Generates a new demo <see cref="DataTable"/> with the given number of <paramref name="cols"/> (min 4) 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();
+
+			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)));
+
+			for(int i=0;i< cols -4; i++) {
+				dt.Columns.Add("Column" + (i+4));
+			}
+			
+			var r = new Random(100);
+
+			for(int i=0;i< rows;i++) {
+				
+				List<object> row = new List<object>(){ 
+					"Some long text with unicode '😀'",
+					new DateTime(2000+i,12,25),
+					r.Next(i),
+					r.NextDouble()*i
+				};
+				
+				for(int j=0;j< cols -4; j++) {
+					row.Add("SomeValue" + r.Next(100));
+				}
+
+				dt.Rows.Add(row.ToArray());
+			}
+
+			return dt;
+		}
+	}
+}