Linqpad Extension method to generate csv with class (keep strongly typed) (Temp Tables in LinqPad)

1readme.md

##Preparation:

1. Get Nuget CsvHelper

2. Copy extension method to My Extensions in LinqPad

##Usage:

1. Write your query (C# Statements)

Company.Take(100).DumpAsClassAndCsv("Company", "100 first companies");

2. The extension saves a csv with the actual data + a linqpad C# code file into a subfolder in your Linqpad My Queries folder. The code file has a class definition + code to read the data from the csv into a strongly typed list (i.e. IEnumerable).

3. Open the generated linqpad file from the My Queries window and run it as is, or combine it with more queries.

2SampleGenerated.cs

// 100 first companies
// Generated 2014-08-19 13:48:40
void Main() {
    var companiesallEnumerable=GetCompanyRecords(@"C:\linqpad\my queries\company\100 first companies.csv");
    companiesallEnumerable.Dump();
}
public IEnumerable<Company> GetCompanyRecords(string filePath){
    var csvReader = new CsvHelper.CsvReader(File.OpenText(fileName));  
    return csvReader.GetRecords<Company>();
}
public class Company {
    public Int32 Id {get;set;}
    public String Name {get;set;}
    public DateTime? RegDate {get;set;}
    public String Type {get;set;}
}

MyExtensions.cs

public static class MyExtensions
{
	// Write custom extension methods here. They will be available to all queries.
	public static string CodeGen(this Type type, string typeName, string description, string filePath){
	
		var t = new StringBuilder();
	
		var className = type.Name.StartsWith("<>")?"AnonymousType":type.Name;				
		
		if (typeName!="") className = typeName;
		
		var listName = className.ToLower() + "Enumerable";				
		
		
		if (description!="")
			t.AppendLine("// " + description);
		t.AppendLine("// Generated " + DateTime.Now.ToString());
		
		t.AppendLine("void Main() {");
		t.AppendLine("    var " + listName + @"=Get" + typeName + @"Records(@""" + filePath + @""");");
		t.AppendLine("    " + listName + ".Dump();");
			
		t.AppendLine("}");
		
		t.AppendLine(@"public IEnumerable<" + className + "> Get" + typeName + "Records(string filePath){");
		t.AppendLine(@"    var csvReader = new CsvHelper.CsvReader(File.OpenText(filePath));");
		t.AppendLine(@"    return csvReader.GetRecords<" + className + @">();");
		t.AppendLine("}");
		
	
		t.AppendLine("public class " + className + " {");
		
		type.GetFields().Select (x => new {Name=x.Name, Type=(x.FieldType.IsGenericType && x.FieldType.GetGenericTypeDefinition()==typeof(Nullable<>))?Nullable.GetUnderlyingType(x.FieldType).Name + "?":x.FieldType.Name}).ToList().ForEach(row=>{	
			t.AppendLine("    public " + row.Type + " " + row.Name + " {get;set;}");	
		});
		
		type.GetProperties().Select(x=>new { Name = x.Name, Type = x.PropertyType.Name}).ToList().ForEach(row=>{
			t.AppendLine("    public " + row.Type + " " + row.Name + " {get;set;}");	
		});
		
		t.AppendLine("}");		
		
		
		return t.ToString();

	}
	
	public static void DumpAsClassAndCsv<TIn>(this IEnumerable<TIn> records, string typeName, string queryDescription){
	
		var path = Path.GetDirectoryName(Util.CurrentQueryPath);
		
		if (path !=null) {				
		
			path = path + "/" + typeName;
			Directory.CreateDirectory(path);
			var csvPath = path + "/" + queryDescription + ".csv";
			Util.WriteCsv(records, csvPath);			
			
			var code = CodeGen(records.First().GetType(), typeName, queryDescription, csvPath);		
			
			var sb = new StringBuilder();
			sb.AppendLine(@"<Query Kind=""Program"">");
			sb.AppendLine(@"<NuGetReference>CsvHelper</NuGetReference>");
			sb.AppendLine(@"</Query>");
			sb.AppendLine(code);						
			
			var codeFilePath = path + "/" + queryDescription + ".linq";
			File.WriteAllText(codeFilePath,sb.ToString());		
			
			Console.WriteLine("Generated file " + codeFilePath);
			
		} else {
		
			throw new Exception("Save current query first");
		
		}
		
	}
	
}