HowTo Filter System.IO.Directory.GetFiles with Linq
30 May 2008Here we are going to see an easy way to enumerate files in a directory, filter the files with Linq, then bind the results to a ASP.NET repeater control. We will show you the old .NET 1x way of doing this, then the new and improved Linq way of doing this.
I had a method that would return a DataTable as results, then bind it to a ASP.NET Repeater control to display the file list of Exception Reports.
Old .NET 1.1 way of filtering a GetFiles list and returning as a bindable object
DataTable dtFiles = new DataTable();
dtFiles.Columns.Add("FullName", typeof(string));
dtFiles.Columns.Add("FileName", typeof(string));
foreach (string file in Directory.GetFiles(Server.MapPath("~/App_Data")))
{
if (!file.Contains("ErrorReport"))
continue;
DataRow row = dtFiles.NewRow();
row["FullName"] = file;
row["FileName"] = System.IO.Path.GetFileName(file);
dtFiles.Rows.Add(row);
}
this.repeaterFiles.DataSource = dtFiles;
this.repeaterFiles.DataBind();
Here is how to filter your GetFiles results with Linq
var fileList = from file in Directory.GetFiles(Server.MapPath("~/App_Data"))
where file.Contains("ErrorReport")
select new
{
FullName = file,
FileName = System.IO.Path.GetFileName(file)
};
this.repeaterFiles.DataSource = dtFiles;
this.repeaterFiles.DataBind();
You can see this is much cleaner, no need to create a DataTable with the results. By using the "select new" you are basically creating a collection with two properties (FullName, FileName) on the fly.
I found Pro LINQ to be an excellent read on the Linq subject.
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