drafts\【LazyLoading】IEnumerable extract code lazy loading show Stream was not readable.linq

drafts/【LazyLoading】IEnumerable extract code lazy loading show Stream was not readable.linq

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+<Query Kind="Program">
+  <NuGetReference>Dapper</NuGetReference>
+  <NuGetReference>MiniExcel</NuGetReference>
+  <NuGetReference>Newtonsoft.Json</NuGetReference>
+  <NuGetReference>System.Data.SqlClient</NuGetReference>
+  <Namespace>MiniExcelLibs</Namespace>
+  <Namespace>Newtonsoft.Json</Namespace>
+  <RemoveNamespace>System.Data</RemoveNamespace>
+  <RemoveNamespace>System.Diagnostics</RemoveNamespace>
+  <RemoveNamespace>System.Linq.Expressions</RemoveNamespace>
+  <RemoveNamespace>System.Text</RemoveNamespace>
+  <RemoveNamespace>System.Text.RegularExpressions</RemoveNamespace>
+  <RemoveNamespace>System.Threading</RemoveNamespace>
+  <RemoveNamespace>System.Transactions</RemoveNamespace>
+  <RemoveNamespace>System.Xml</RemoveNamespace>
+  <RemoveNamespace>System.Xml.Linq</RemoveNamespace>
+  <RemoveNamespace>System.Xml.XPath</RemoveNamespace>
+</Query>
+
+//// [c# - yield return statement inside a using() { } block Disposes before executing - Stack Overflow](https://stackoverflow.com/questions/1539114/yield-return-statement-inside-a-using-block-disposes-before-executing)
+void Main()
+{
+	var path = Path.Combine(Path.GetTempPath(), $"{Guid.NewGuid()}.csv");
+	var csv =
+@"1,2
+3,4";
+	File.WriteAllText(path, csv);
+
+	Console.WriteLine(Test1(path).ToList()); //Ok
+	//Console.WriteLine(Test2(path).ToList()); //Error
+	//Console.WriteLine(Test4(path).ToList()); //Error
+	Console.WriteLine(Test6(path).ToList()); //OK
+}
+
+// You can define other methods, fields, classes and namespaces here
+
+IEnumerable<string[]> Test1(string path)
+{
+	using (var stream = File.OpenRead(path))
+	using (var reader = new StreamReader(stream))
+	{
+		var row = string.Empty;
+		while ((row = reader.ReadLine()) != null)
+			yield return row.Split(new[] { ',' }, StringSplitOptions.None);
+	}
+}
+
+IEnumerable<string[]> Test4(string path)
+{
+	using (var stream = File.OpenRead(path))
+	using (var reader = new StreamReader(stream))
+		return Test5(reader).AsEnumerable();
+}
+
+
+IEnumerable<string[]> Test5(StreamReader reader)
+{
+	var row = string.Empty;
+	while ((row = reader.ReadLine()) != null)
+		yield return row.Split(new[] { ',' }, StringSplitOptions.None);
+}
+
+IEnumerable<string[]> Test6(string path)
+{
+	using (var stream = File.OpenRead(path))
+	using (var reader = new StreamReader(stream))
+		foreach (var element in Test7(reader))
+		{
+			yield return element;
+		}
+
+}
+
+IEnumerable<string[]> Test7(StreamReader reader)
+{
+	var row = string.Empty;
+	while ((row = reader.ReadLine()) != null)
+		yield return row.Split(new[] { ',' }, StringSplitOptions.None);
+}
+
+IEnumerable<string[]> Test2(string path)
+{
+	using (var stream = File.OpenRead(path))
+		return Test3(stream);
+}
+
+IEnumerable<string[]> Test3(Stream stream)
+{
+	using (var reader = new StreamReader(stream))
+	{
+		var row = string.Empty;
+		while ((row = reader.ReadLine()) != null)
+			yield return row.Split(new[] { ',' }, StringSplitOptions.None);
+	}
+}