XML - Dataset retrieving specific rows from dataset

Question

I've been at this for quite some time but to no avail. I have an xml file that is structured like the following (I've simplified for readability). I can only be certain that the recipe id is unique. I need to pull the settings for just recipe1.group1. I can get the file into an xml reader and then into a dataset from there. How do I filter on the data set to just get the setting rows for recipe1.group1? Ideally I'd like something like the following pseudo-code. DataTable settings = RecipeDataSet.Tables.Select('Get settings from Group where Recipe='recipe1' and Group='group1') Thanks SteveJ etc......

Mahesh Chand · Answer

I think you're better off using XPath query to search XML instead of using DataSet/DataTable combination. Use Select or SelectNodes method of XmlDocument and you can use XPath in that.

Steve Jackson · Answer

Thanks Mahesh; I've concluded the same thing. For those that are stumbling on this later something like the following seems to work for me. myXmlDoc.load(filename.xml); string _xpath = String.format(@/doc_element/recipe[@id= {0} ]/group[@id= {1} ]/setting; XmlNode _rootElement = myXmlDoc.DocumentElement; XmlNodeList _matchingSettings = root.SelectNodes(_xpath); foreach (xmlNode _node in _matchingSettings){ ............................ } I didn't test the above but it should get someone started. Also see the W3C web page for xpaths - it is really useful. http://www.w3schools.com/xpath/xpath_syntax.asp Cheers;

Steve Jackson · Answer

Thanks Mahesh; I did look at select but couldn't get the details worked out. The difficulty is that I want to sort a table based on what parent it belonged to which I can't seem to work out. In my example above I want to sort settings based on the id of recipe and group. Maybe a better way to ask the question would be to know if I can extract sub tables from tables. That is to say If I pull the recipe table from the dataset can I pull from it the group table then the settings table (only including the desired settings?) Pseudo: Get recipe table from xml-based dataset From recipe table get only rows for recipe id='recipe1' call it recipe1 table From recipe1 table get only group1 rows call it group1 table From group1 table get the settings table.

Mahesh Chand · Answer

Did you look at DataTable.Select method. Here is an example. string strExpr; string strSort; strExpr = id > 5; // Sort descending by column named CompanyName. strSort = name DESC; // Use the Select method to find all rows matching the filter. DataRow[] foundRows = customerTable.Select( strExpr strSort DataViewRowState.Added );

XML -> Dataset, retrieving specific rows from dataset