RSCG- part 13 – IFormattable
| name | IFormattable |
| nuget |
https://www.nuget.org/packages/AOPMethodsCommon/ |
| link | http://msprogrammer.serviciipeweb.ro/category/roslyn/ |
| author | Andrei Ignat |
This will generate code to add IFormattable to any class, based on the properties of the class
The code that you start with is
[AutoMethods(CustomTemplateFileName = "CreateFormattable.txt", template = TemplateMethod.CustomTemplateFile)]
partial class Department
{
public int ID { get; set; }
public string Name { get; set; }
}
[AutoMethods(CustomTemplateFileName = "CreateFormattable.txt", template = TemplateMethod.CustomTemplateFile)]
partial class Employee
{
public int ID { get; set; }
public string Name { get; set; }
public Department dep { get; set; }
}
The code that you will use is
var e = new Employee();
e.ID = 1;
e.Name = "Andrei";
e.dep = new Department();
e.dep.Name = "IT";
Console.WriteLine(e.ToString("for employee with id = {id} the name is {name} and department is {dep?.Name}", null));
e.dep = null;
Console.WriteLine(e.ToString("for employee with id = {id} the name is {name} and department is {dep?.Name}", null));
The code that is generated is
[GeneratedCode("AOPMethods", "2021.2.27.640")]
[DebuggerDisplay(" ID = {ID} Name = {Name} dep = {dep}")]
partial class Employee: IFormattable{
public object ValueProperty(string val){
val = val.Replace("?","");
if(string.Compare("ID",val,StringComparison.CurrentCultureIgnoreCase)==0) {
return this.ID;
}
if(string.Compare("Name",val,StringComparison.CurrentCultureIgnoreCase)==0) {
return this.Name;
}
if(string.Compare("dep",val,StringComparison.CurrentCultureIgnoreCase)==0) {
return this.dep;
}
throw new ArgumentException("cannot find "+ val);
}
//adapted from https://haacked.com/archive/2009/01/14/named-formats-redux.aspx/
private object Eval(string expression,IFormatProvider formatProvider)
{
if (expression.Contains("."))
{
var splut = expression.Split(".");
bool canBeNull=splut[0].Contains("?");
dynamic d = ValueProperty(splut[0]);
if(canBeNull && d == null)
return null;
for(var i=1; i<splut.Length;i++){
canBeNull=splut[i].Contains("?");
d=d.ToString("{"+splut[i]+"}",formatProvider);
if(canBeNull && d == null)
return null;
}
return d;
}
return ValueProperty(expression);
}
public string ToString(string format, IFormatProvider formatProvider)
{
if (format == null)
throw new ArgumentNullException("format");
List<object> values = new List<object>();
string rewrittenFormat = Regex.Replace(format,
delegate (Match m)
{
Group startGroup = m.Groups["start"];
Group propertyGroup = m.Groups["property"];
Group formatGroup = m.Groups["format"];
Group endGroup = m.Groups["end"];
values.Add((propertyGroup.Value == "0")
? this
: Eval(propertyGroup.Value, formatProvider));
int openings = startGroup.Captures.Count;
int closings = endGroup.Captures.Count;
return openings > closings || openings % 2 == 0
? m.Value
: new string('{', openings) + (values.Count - 1)
+ formatGroup.Value
+ new string('}', closings);
},
RegexOptions.Compiled
| RegexOptions.CultureInvariant
| RegexOptions.IgnoreCase);
return string.Format(formatProvider, rewrittenFormat, values.ToArray());
}
}
Example Code: https://github.com/ignatandrei/RSCG_Examples/tree/main/IFormattable
Leave a Reply