73 datagrid display a custom text in the body of the grid when there are no data

doc/changelog.txt

@@ -11,6 +11,7 @@ ver 1.2.0
 - [feature] DataGrid: Added support for displaying horizontal border lines between any two content rows.
 - [feature] DataGrid: Implemented grid MinWidth and MaxWidth.
 - [feature] DataGrid: Added top and bottom padding to the data grid cells.
+- [feature] DataGrid: Added ContentOverflow property for cells to control the overflow behavior.
 
 
 ver 1.1.0

sources/ConsoleTools/ConsoleTools.Controls.Tables/CellBase.cs

@@ -58,6 +58,11 @@ public abstract class CellBase
     /// </summary>
     public static int DefaultPaddingBottom => 0;
 
+    /// <summary>
+    /// Gets or sets the row that contains the current cell.
+    /// </summary>
+    public RowBase ParentRow { get; internal set; }
+
     /// <summary>
     /// Gets or sets the content of the cell.
     /// </summary>

sources/ConsoleTools/ConsoleTools.Controls.Tables/ColumnList.cs

@@ -32,12 +32,25 @@ public class ColumnList : IEnumerable<Column>
 {
     private readonly DataGrid parentDataGrid;
     private readonly List<Column> columns = new();
+    private HeaderRow headerRow;
 
     /// <summary>
     /// Gets the number of columns contained in the current instance.
     /// </summary>
     public int Count => columns.Count;
 
+    public HeaderRow HeaderRow
+    {
+        get => headerRow;
+        set
+        {
+            headerRow = value;
+
+            foreach (Column column in columns) 
+                column.HeaderCell.ParentRow = value;
+        }
+    }
+
     /// <summary>
     /// Gets the <see cref="Column"/> at the specified index.
     /// If the index is outside of the bounds of the list, <c>null</c> is returned.

sources/ConsoleTools/ConsoleTools.Controls.Tables/ContentCell.cs

@@ -30,11 +30,6 @@ public class ContentCell : CellBase
 {
     private int columnSpan = 1;
 
-    /// <summary>
-    /// Gets or sets the row that contains the current cell.
-    /// </summary>
-    public ContentRow ParentRow { get; internal set; }
-
     /// <summary>
     /// Gets or sets a value that specifies across how many columns should the cell be displayed.
     /// </summary>
@@ -188,22 +183,10 @@ public override int CalculatePaddingRight()
     [Obsolete("Intended for internal usage only.")]
     public override ConsoleColor? CalculateForegroundColor()
     {
-        ConsoleColor? color = ForegroundColor;
-        if (color != null)
-            return color;
-
-        color = ParentRow?.ForegroundColor;
-        if (color != null)
-            return color;
-
-        Column column = GetColumn();
-        color = column?.ForegroundColor;
-        if (color != null)
-            return color;
-
-        color = ParentRow?.ParentDataGrid?.ForegroundColor;
-
-        return color;
+        return ForegroundColor
+               ?? ParentRow?.ForegroundColor
+               ?? GetColumn()?.ForegroundColor
+               ?? ParentRow?.ParentDataGrid?.ForegroundColor;
     }
 
     /// <summary>
@@ -213,22 +196,10 @@ public override int CalculatePaddingRight()
     [Obsolete("Intended for internal usage only.")]
     public override ConsoleColor? CalculateBackgroundColor()
     {
-        ConsoleColor? color = BackgroundColor;
-        if (color != null)
-            return color;
-
-        color = ParentRow?.BackgroundColor;
-        if (color != null)
-            return color;
-
-        Column column = GetColumn();
-        color = column?.BackgroundColor;
-        if (color != null)
-            return color;
-
-        color = ParentRow?.ParentDataGrid?.BackgroundColor;
-
-        return color;
+        return BackgroundColor
+               ?? ParentRow?.BackgroundColor
+               ?? GetColumn()?.BackgroundColor
+               ?? ParentRow?.ParentDataGrid?.BackgroundColor;
     }
 
     /// <summary>

sources/ConsoleTools/ConsoleTools.Controls.Tables/ContentRow.cs

@@ -249,9 +249,12 @@ public ContentCell AddCell(object cellContent)
     /// Returns the index of the specified cell.
     /// If the cell is not part of the current <see cref="ContentRow"/> instance, returns <c>null</c>.
     /// </summary>
-    public int? IndexOfCell(ContentCell cell)
+    public override int? IndexOfCell(CellBase cell)
     {
-        int indexOfCell = cells.IndexOf(cell);
+        if (cell is not ContentCell contentCell)
+            return null;
+
+        int indexOfCell = cells.IndexOf(contentCell);
 
         return indexOfCell == -1
             ? null

sources/ConsoleTools/ConsoleTools.Controls.Tables/DataGrid.cs

@@ -37,6 +37,7 @@ public class DataGrid : BlockControl
     private TitleRow titleRow;
     private HeaderRow headerRow;
     private DataGridBorder border;
+    private EmptyMessageRow emptyMessageRow;
     private FooterRow footerRow;
 
     /// <summary>
@@ -302,6 +303,30 @@ public bool IsBorderVisible
         set => Border.IsVisible = value;
     }
 
+    /// <summary>
+    /// Gets the row containing the message to be displayed in the content area when there is no
+    /// data in the grid.
+    /// </summary>
+    public EmptyMessageRow EmptyMessageRow
+    {
+        get => emptyMessageRow;
+        private set
+        {
+            emptyMessageRow = value;
+            emptyMessageRow.ParentDataGrid = this;
+        }
+    }
+
+    /// <summary>
+    /// Gets or sets the text to be displayed in the content area when there is no data in the
+    /// grid.
+    /// </summary>
+    public MultilineText EmptyMessage
+    {
+        get => EmptyMessageRow.EmptyMessageCell.Content;
+        set => EmptyMessageRow.EmptyMessageCell.Content = value;
+    }
+
     /// <summary>
     /// Initializes a new instance of the <see cref="DataGrid"/> class.
     /// </summary>
@@ -312,6 +337,7 @@ public DataGrid()
         HeaderRow = new HeaderRow(Columns);
         TitleRow = new TitleRow();
         FooterRow = new FooterRow();
+        EmptyMessageRow = new EmptyMessageRow();
         Border = new DataGridBorder();
     }
 
@@ -326,6 +352,7 @@ public DataGrid(string title)
         HeaderRow = new HeaderRow(Columns);
         TitleRow = new TitleRow(title);
         FooterRow = new FooterRow();
+        EmptyMessageRow = new EmptyMessageRow();
         Border = new DataGridBorder();
     }
 
@@ -340,6 +367,7 @@ public DataGrid(MultilineText title)
         HeaderRow = new HeaderRow(Columns);
         TitleRow = new TitleRow(title);
         FooterRow = new FooterRow();
+        EmptyMessageRow = new EmptyMessageRow();
         Border = new DataGridBorder();
     }
 
@@ -354,6 +382,7 @@ public DataGrid(object title)
         HeaderRow = new HeaderRow(Columns);
         TitleRow = new TitleRow(title);
         FooterRow = new FooterRow();
+        EmptyMessageRow = new EmptyMessageRow();
         Border = new DataGridBorder();
     }
 

sources/ConsoleTools/ConsoleTools.Controls.Tables/EmptyMessageCell.cs

@@ -0,0 +1,117 @@
+// ConsoleTools
+// Copyright (C) 2017-2024 Dust in the Wind
+// 
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+// 
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+// 
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System;
+
+namespace DustInTheWind.ConsoleTools.Controls.Tables;
+
+/// <summary>
+/// Represents the sing;e cell displayed in the <see cref="EmptyMessageRow"/>.
+/// It contains a message to be displayed to the user in the content area when the
+/// <see cref="DataGrid"/> contains no content rows.
+/// </summary>
+public class EmptyMessageCell : CellBase
+{
+    /// <summary>
+    /// Initializes a new instance of the <see cref="EmptyMessageCell" /> class with
+    /// empty content.
+    /// </summary>
+    public EmptyMessageCell()
+    {
+        PaddingLeft = 10;
+        PaddingTop = 1;
+        PaddingRight = 10;
+        PaddingBottom = 1;
+        HorizontalAlignment = HorizontalAlignment.Center;
+    }
+
+    /// <inheritdoc />
+    [Obsolete("Intended for internal usage only.")]
+    public override ConsoleColor? CalculateForegroundColor()
+    {
+        return ForegroundColor
+               ?? ParentRow?.ForegroundColor
+               ?? ParentRow?.ParentDataGrid?.ForegroundColor;
+    }
+
+    /// <inheritdoc />
+    [Obsolete("Intended for internal usage only.")]
+    public override ConsoleColor? CalculateBackgroundColor()
+    {
+        return BackgroundColor
+               ?? ParentRow?.BackgroundColor
+               ?? ParentRow?.ParentDataGrid?.BackgroundColor;
+    }
+
+    /// <inheritdoc />
+    [Obsolete("Intended for internal usage only.")]
+    public override int CalculatePaddingLeft()
+    {
+        int? paddingLeft = PaddingLeft;
+        if (paddingLeft != null)
+            return paddingLeft.Value;
+
+        paddingLeft = DefaultPaddingLeft;
+
+        return paddingLeft.Value;
+    }
+
+    /// <inheritdoc />
+    [Obsolete("Intended for internal usage only.")]
+    public override int CalculatePaddingRight()
+    {
+        int? paddingRight = PaddingRight;
+        if (paddingRight != null)
+            return paddingRight.Value;
+
+        paddingRight = DefaultPaddingRight;
+
+        return paddingRight.Value;
+    }
+
+    /// <inheritdoc />
+    [Obsolete("Intended for internal usage only.")]
+    public override HorizontalAlignment CalculateHorizontalAlignment()
+    {
+        HorizontalAlignment alignment = HorizontalAlignment;
+        if (alignment != HorizontalAlignment.Default)
+            return alignment;
+
+        alignment = CalculateHorizontalAlignmentAtRowLevel();
+        if (alignment != HorizontalAlignment.Default)
+            return alignment;
+
+        alignment = DefaultHorizontalAlignment;
+
+        return alignment;
+    }
+
+    private HorizontalAlignment CalculateHorizontalAlignmentAtRowLevel()
+    {
+        return ParentRow?.CellHorizontalAlignment ?? HorizontalAlignment.Default;
+    }
+
+    internal override CellContentOverflow ComputeContentOverflow()
+    {
+        CellContentOverflow contentOverflow = ContentOverflow;
+        if (contentOverflow != CellContentOverflow.Default)
+            return contentOverflow;
+
+        contentOverflow = DefaultContentOverflow;
+
+        return contentOverflow;
+    }
+}