DataTableOverview: .NET 10 and the article's order

csharp-intermediate-topics/DataTableOverview/DataTableOverview/DataTableOverview.csproj

@@ -2,14 +2,11 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
   </PropertyGroup>
 
-  <ItemGroup>
-    <None Remove="vegtable-sales.csv" />
-  </ItemGroup>
   <ItemGroup>
     <Content Include="vegetable-sales.csv">
       <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>

csharp-intermediate-topics/DataTableOverview/DataTableOverview/Program.cs

@@ -9,17 +9,21 @@ public static void Main(string[] args)
             var dt = CreateMainDataTable();
 
             PopulateDataTable(dt);
+            AddPrimaryKey(dt);
+            PrintConstraints(dt);
             PrintData(dt);
 
             DataTable dtClone = dt.Clone();
-            PrintColumns(dtClone);          
+            PrintColumns(dtClone);
 
             DataTable dtCopy = dt.Copy();
             PrintData(dtCopy);
 
             AddNewRow(dt);
             FilterDataTable(dt);
 
+            PrintTable(dt);
+
             SalesDataProcessor.ProcessSales();
         }
 
@@ -32,45 +36,41 @@ public static DataTable CreateMainDataTable()
             dt.Columns.Add("Date", typeof(DateTime));
             dt.Columns.Add("Price", typeof(double));
 
-            // add primary key
-            var pkCol = new DataColumn("Key", typeof(int));
-            dt.Columns.Add(pkCol);
-
-            var pkCols = new DataColumn[1];
-            pkCols[0] = pkCol;
-
-            dt.PrimaryKey = pkCols;
-
             return dt;
         }
 
         public static void PopulateDataTable(DataTable dt)
         {
-            // add row
             // 1) declare and instantiate row
-            DataRow row;
-            row = dt.NewRow();
+            DataRow row = dt.NewRow();
 
             // 2) set column values
             row["Ticker"] = "MSFT";
             row["Date"] = new DateTime(2023, 3, 3);
-            row["Price"] = 255.29;  
-            row["Key"] = 0;
+            row["Price"] = 255.29;
 
             // by Ordinal/index
             row[0] = "MSFT";
             row[1] = new DateTime(2023, 3, 3);
             row[2] = 255.29;
-            row[3] = 0;
 
             // 3) add populated row to table
             dt.Rows.Add(row);
         }
 
+        public static void AddPrimaryKey(DataTable dt)
+        {
+            var pkCol = new DataColumn("Key", typeof(int));
+            dt.Columns.Add(pkCol);
+
+            dt.Rows[0]["Key"] = 0;
+
+            dt.PrimaryKey = [pkCol];
+        }
+
         public static void AddNewRow(DataTable dt)
         {
-            DataRow row;
-            row = dt.NewRow();
+            DataRow row = dt.NewRow();
 
             row["Ticker"] = "AMZN";
             row["Date"] = new DateTime(2023, 3, 6);
@@ -80,6 +80,11 @@ public static void AddNewRow(DataTable dt)
             dt.Rows.Add(row);
         }
 
+        public static void AddNewRowFromValues(DataTable dt)
+        {
+            dt.Rows.Add("AMZN", new DateTime(2023, 3, 6), 93.75, 1);
+        }
+
         public static void PrintConstraints(DataTable dt)
         {
             foreach (Constraint constraint in dt.Constraints)
@@ -124,5 +129,21 @@ public static void PrintData(DataTable dt)
                 }
             }
         }
+
+        public static void PrintTable(DataTable dt)
+        {
+            var header = dt.Columns.Cast<DataColumn>().Select(col => col.ColumnName);
+            Console.WriteLine(string.Join(" | ", header));
+
+            foreach (DataRow row in dt.Rows)
+                Console.WriteLine(string.Join(" | ", row.ItemArray));
+        }
+
+        public static IEnumerable<string?> GetTickersBelow(DataTable dt, double price)
+        {
+            return dt.AsEnumerable()
+                .Where(row => row.Field<double>("Price") < price)
+                .Select(row => row.Field<string>("Ticker"));
+        }
     }
-}
+}

csharp-intermediate-topics/DataTableOverview/DataTableOverview/SalesDataProcessor.cs

@@ -16,21 +16,21 @@ public static void ProcessSales()
 
         public static DataTable CsvToDataTable(string filePath)
         {
-            DataTable dtRes = new DataTable();
+            var dtRes = new DataTable();
             using (var parser = new TextFieldParser(filePath))
             {
                 parser.TextFieldType = FieldType.Delimited;
                 parser.TrimWhiteSpace = true;
                 parser.SetDelimiters(",");
 
-                var columns = parser.ReadFields();
+                var columns = parser.ReadFields() ?? [];
 
                 foreach (var col in columns)
                     dtRes.Columns.Add(col);
 
                 while (!parser.EndOfData)
                 {
-                    var row = parser.ReadFields();
+                    var row = parser.ReadFields() ?? [];
                     dtRes.LoadDataRow(row, true);
                 }
             }

csharp-intermediate-topics/DataTableOverview/DataTableOverview/vegetable-sales.csv

@@ -5,7 +5,7 @@ Pepper,2,2,4
 Cucumber,4,1,4
 Lettuce,6,0.5,3
 Asparagus,2,2.5,5
-Carrot,1,3,1
+Carrot,1,3,3
 Broccoli,2,0.75,1.5
 Pepper,4,2,8
 Cucumber,7,1,7

csharp-intermediate-topics/DataTableOverview/Tests/ProgramTests.cs

@@ -5,13 +5,23 @@
 
 namespace Tests
 {
+    [Collection("Console output")]
     public class ProgramTests
     {
+        private static DataTable CreateKeyedTable()
+        {
+            var dt = Program.CreateMainDataTable();
+            Program.PopulateDataTable(dt);
+            Program.AddPrimaryKey(dt);
+
+            return dt;
+        }
+
         [Fact]
         public static void WhenCreateMainDataTable_ThenColumnsPopulateCorrectly()
         {
             var dt = Program.CreateMainDataTable();
-            var expectedColumns = new string[] { "Ticker", "Date", "Price", "Key" };
+            var expectedColumns = new string[] { "Ticker", "Date", "Price" };
 
             var actualColumns = dt.Columns.Cast<DataColumn>()
                 .Select(x => x.ColumnName)
@@ -21,13 +31,25 @@ public static void WhenCreateMainDataTable_ThenColumnsPopulateCorrectly()
         }
 
         [Fact]
-        public static void WhenCreateMaindataTable_ThenPrimaryKeyEqualsKey()
+        public static void WhenAddPrimaryKey_ThenPrimaryKeyEqualsKey()
         {
-            var dt = Program.CreateMainDataTable();
+            var dt = CreateKeyedTable();
 
             var pkActual = dt.PrimaryKey;
 
             Assert.Equal("Key", pkActual[0].Caption);
+            Assert.Equal(0, dt.Rows[0]["Key"]);
+        }
+
+        [Fact]
+        public static void WhenPrimaryKeySetOnColumnWithEmptyValues_ThenDataExceptionThrown()
+        {
+            var dt = Program.CreateMainDataTable();
+            Program.PopulateDataTable(dt);
+            var pkCol = new DataColumn("Key", typeof(int));
+            dt.Columns.Add(pkCol);
+
+            Assert.Throws<DataException>(() => dt.PrimaryKey = [pkCol]);
         }
 
         [Fact]
@@ -43,17 +65,36 @@ public static void WhenPopulateDataTable_ThenDataTableContainsMsftRecord()
         [Fact]
         public static void WhenAddNewRow_ThenDataTableContainsAmznRecord()
         {
-            var dt = Program.CreateMainDataTable();
+            var dt = CreateKeyedTable();
 
             Program.AddNewRow(dt);
 
-            Assert.Contains("AMZN", Convert.ToString(dt.Rows[0][0]));
+            Assert.Contains("AMZN", Convert.ToString(dt.Rows[1][0]));
+        }
+
+        [Fact]
+        public static void WhenAddNewRowFromValues_ThenDataTableContainsAmznRecord()
+        {
+            var dt = CreateKeyedTable();
+
+            Program.AddNewRowFromValues(dt);
+
+            Assert.Equal("AMZN", dt.Rows[1]["Ticker"]);
+            Assert.Equal(1, dt.Rows[1]["Key"]);
+        }
+
+        [Fact]
+        public static void WhenRowAddedWithDuplicateKey_ThenConstraintExceptionThrown()
+        {
+            var dt = CreateKeyedTable();
+
+            Assert.Throws<ConstraintException>(() => dt.Rows.Add("AMZN", new DateTime(2023, 3, 6), 93.75, 0));
         }
 
         [Fact]
         public static void WhenPrintConstraints_ThenReturnsConstraintOneUniqueConstraint()
         {
-            var dt = Program.CreateMainDataTable();
+            var dt = CreateKeyedTable();
 
             var stringWriter = new StringWriter();
             Console.SetOut(stringWriter);
@@ -65,10 +106,21 @@ public static void WhenPrintConstraints_ThenReturnsConstraintOneUniqueConstraint
             Assert.Contains("System.Data.UniqueConstraint", output);
         }
 
+        [Fact]
+        public static void WhenCloneCalled_ThenAllColumnsAndNoRowsCopied()
+        {
+            var dt = CreateKeyedTable();
+
+            var dtClone = dt.Clone();
+
+            Assert.Equal(4, dtClone.Columns.Count);
+            Assert.Empty(dtClone.Rows);
+        }
+
         [Fact]
         public static void WhenFilterDataTable_ThenPrintsAmznDataRow()
         {
-            var dt = Program.CreateMainDataTable();
+            var dt = CreateKeyedTable();
             Program.AddNewRow(dt);
 
             var stringWriter = new StringWriter();
@@ -78,13 +130,13 @@ public static void WhenFilterDataTable_ThenPrintsAmznDataRow()
             var output = stringWriter.ToString();
 
             Assert.Contains("AMZN", output);
+            Assert.DoesNotContain("MSFT", output);
         }
 
         [Fact]
         public static void WhenPrintData_ThenPrintsExpectedData()
         {
-            var dt = Program.CreateMainDataTable();
-            Program.PopulateDataTable(dt);
+            var dt = CreateKeyedTable();
 
             var stringWriter = new StringWriter();
             Console.SetOut(stringWriter);
@@ -95,7 +147,35 @@ public static void WhenPrintData_ThenPrintsExpectedData()
             Assert.Contains("MSFT", output);
             Assert.Contains(Convert.ToString(new DateTime(2023, 3, 3)), output);
             Assert.Contains("255.29", output);
-            Assert.Contains("0", output);
+            Assert.Contains("Key: 0", output);
+        }
+
+        [Fact]
+        public static void WhenPrintTable_ThenPrintsHeaderAndOneLinePerRow()
+        {
+            var dt = CreateKeyedTable();
+            Program.AddNewRow(dt);
+
+            var stringWriter = new StringWriter();
+            Console.SetOut(stringWriter);
+
+            Program.PrintTable(dt);
+            var lines = stringWriter.ToString().Split(Environment.NewLine, StringSplitOptions.RemoveEmptyEntries);
+
+            Assert.Equal("Ticker | Date | Price | Key", lines[0]);
+            Assert.Equal(3, lines.Length);
+            Assert.StartsWith("AMZN | ", lines[2]);
+        }
+
+        [Fact]
+        public static void WhenGetTickersBelow_ThenReturnsOnlyCheaperTickers()
+        {
+            var dt = CreateKeyedTable();
+            Program.AddNewRow(dt);
+
+            var tickers = Program.GetTickersBelow(dt, 100);
+
+            Assert.Equal(new[] { "AMZN" }, tickers);
         }
     }
-}
+}

csharp-intermediate-topics/DataTableOverview/Tests/SalesDataProcessorTests.cs

@@ -1,10 +1,10 @@
 using DataTableOverview;
-using Microsoft.VisualStudio.TestPlatform.TestHost;
 using Xunit;
 using System;
 
 namespace Tests
 {
+    [Collection("Console output")]
     public class SalesDataProcessorTests
     {
         [Fact]
@@ -32,6 +32,15 @@ public void WhenProcessSales_ThenPrintsSelectedRows()
 
             Assert.Contains("Carrot", output);
         }
+
+        [Fact]
+        public void WhenNumericFilterRunsOnCsvColumn_ThenEvaluateExceptionThrown()
+        {
+            var filePath = AppDomain.CurrentDomain.BaseDirectory + "vegetable-sales.csv";
+            var veggieSales = SalesDataProcessor.CsvToDataTable(filePath);
+
+            Assert.Equal(typeof(string), veggieSales.Columns["Price"]!.DataType);
+            Assert.Throws<System.Data.EvaluateException>(() => veggieSales.Select("Price > 1"));
+        }
     }
 }
-

csharp-intermediate-topics/DataTableOverview/Tests/Tests.csproj

@@ -1,21 +1,21 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net7.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
 
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.3.2" />
-    <PackageReference Include="xunit" Version="2.4.2" />
-    <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5">
+    <PackageReference Include="Microsoft.NET.Test.Sdk" Version="18.11.0" />
+    <PackageReference Include="xunit" Version="2.9.3" />
+    <PackageReference Include="xunit.runner.visualstudio" Version="4.0.1">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>
-    <PackageReference Include="coverlet.collector" Version="3.1.2">
+    <PackageReference Include="coverlet.collector" Version="10.1.0">
       <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
       <PrivateAssets>all</PrivateAssets>
     </PackageReference>