VB.NET 2010 XML Parsing
   I've been through post after post after post for the last few hours trying to figure this out... im new to the XML parsing stuff so I am starting to get frustrated. Here is a sample of the XMl im trying to parse:

 
```
<level id="1">
    <prop n="PROPERTY" v="VALUE"/>
</level>
<level id="2">
    <prop n="PROPERTY" v="VALUE"/>
</level>

```
 I need to be able to decend in to id=1 and id=2 on demand and retrieve property name PROPERTY with its corresponding value VALUE. Can someone point me in the right direction?
Here is a sample of traversing a simple xml structure

 
```
    Dim myxml = <root>
                    <level id="1">
                        <prop n="PROPERTY" v="VALUE"/>
                    </level>
                    <level id="2">
                        <prop n="PROPERTY" v="VALUE"/>
                    </level>
                </root>

    For Each level In myxml.Elements
        Debug.WriteLine("id=" & level.@id.ToString)
        For Each prop In level.Elements
            Debug.WriteLine("n=" & prop.@n.ToString & "  v=" & prop.@v.ToString)
        Next
    Next

```
hi chris, 
if you use relations api, you may set properties field in your query. in this field you should set the names of the properties which values must be retrieved from the server. the argument should be a string in the following format: "propertyname1, propertyname2, , , propertynamen" , wher… For a long time HtmlAgilityPack [didn't had the ability to directly query an attribute value](http://htmlagilitypack.codeplex.com/Thread/View.aspx?ThreadId=1720). You had to loop over the list of meta nodes. Here's one way - 



```
var doc = new HtmlDocument();
doc.LoadHtml(htmlString);

var list = doc.DocumentNode.SelectNodes("//meta"); 
foreach (var node in list)
{
    string content = node.GetAttributeValue("content", "");
}

```

But looks like in there is an [experimental xpath release](http://htmlagilitypack.codeplex.com/releases/view/46681) that will let you do that. 



```
doc.Document.SelectNodes("//meta/@content") 

```

will return a list of HtmlAttribute objects. JavaScript *itself* has nothing built in for handling query string parameters. 


Code running in a (modern) browser you can use the [`URL` object](https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams) (which is part of the APIs provided by browsers to JS):





```
var url_string = "http://www.example.com/t.html?a=1&b=3&c=m2-m3-m4-m5"; //window.location.href
var url = new URL(url_string);
var c = url.searchParams.get("c");
console.log(c);
```









For older browsers (including Internet Explorer), you can use [this polyfill](https://github.com/ungap/url-search-params) or the code from the original version of this answer that predates `URL`:


You could access `location.search`, which would give you from the `?` character on to the end of the URL or the start of the fragment identifier (#foo), whichever comes first.


Then you can parse it with this:





```
function parse_query_string(query) {
  var vars = query.split("&");
  var query_string = {};
  for (var i = 0; i < vars.length; i++) {
    var pair = vars[i].split("=");
    var key = decodeURIComponent(pair[0]);
    var value = decodeURIComponent(pair[1]);
    // If first entry with this name
    if (typeof query_string[key]  "undefined") {
      query_string[key] = decodeURIComponent(value);
      // If second entry with this name
    } else if (typeof query_string[key]  "string") {
      var arr = [query_string[key], decodeURIComponent(value)];
      query_string[key] = arr;
      // If third or later entry with this name
    } else {
      query_string[key].push(decodeURIComponent(value));
    }
  }
  return query_string;
}

var query_string = "a=1&b=3&c=m2-m3-m4-m5";
var parsed_qs = parse_query_string(query_string);
console.log(parsed_qs.c);
```




You can get the query string from the URL of the current page with:



```
var query = window.location.search.substring(1);
var qs = parse_query_string(query);

``` Resolved:  

  

FORM 1.  

  

Copy Code

```
private void btnModificaContractul\_Click(object sender, EventArgs e)
        {


            string[] IDProdusContractPrelugit = new string[dataProduseContract.Rows.Count];
            string[] IDProdusContractRetras = new string[dataProduseContract.Rows.Count];

            for (int i = 0; i < dataProduseContract.Rows.Count; i++)
            {

                if (Convert.ToBoolean(dataProduseContract.Rows[i].Cells[0].Value) == false)
                {
                    IDProdusContractPrelugit[i] = dataProduseContract.Rows[i].Cells[5].Value.ToString();
                }
                else
                {
                    IDProdusContractRetras[i] = dataProduseContract.Rows[i].Cells[5].Value.ToString();
                }
            }

           

            try
            {
                frmModificaContract ModificareContract = new frmModificaContract(IDProdusContractPrelugit, IDProdusContractRetras);
                ModificareContract.ShowDialog();
            }
            catch { MessageBox.Show("Trebuie să selectaţi un contract din listă pentru a edita.", "Datele furnizate sunt incomplete."); }
           
        }
```
  

  

FORM 2.  

  

Copy Code

```
string[] IDProdusContractPrelugit;
        string[] IDProdusContractRetras;

        public frmModificaContract(string[] IDProdusContractPrelugit, string[] IDProdusContractRetras)
        {
            InitializeComponent();
            this.IDProdusContractPrelugit = IDProdusContractPrelugit;
            this.IDProdusContractRetras = IDProdusContractRetras;
            AfisareProduseContract();
        }


        void AfisareProduseContract()
        {

            foreach (string ContractPrelungit in IDProdusContractPrelugit)
            {
                if (ContractPrelungit != null)
                {
                    Program.Connection.CommandText = "select * from ContractItems WHERE ContractItemId=@ContractItemId";
                    Program.Connection.AddParameter("@ContractItemId", ContractPrelungit);

                    DataTable Table = new DataTable();
                    Program.Connection.FillDataTable(Table, true);


                    for (int i = 0; i < Table.Rows.Count; i++)
                    {
                        if (String.IsNullOrWhiteSpace(Table.Rows[i]["DeletedId"].ToString()))
                        {
                            bool validare;
                            validare = true;

                            dataProduseContract.Rows.Add(validare, Table.Rows[i]["Name"].ToString(), Table.Rows[i]["Quantity"].ToString() + " " + Table.Rows[i]["QuantityUnit"].ToString(), Table.Rows[i]["Payment"].ToString(), Table.Rows[i]["Description"].ToString(), Table.Rows[i]["ContractItemId"].ToString());
                        }
                        else
                        {
                            bool validarescos;
                            validarescos = false;
                            dataProduseContract.Rows.Add(validarescos, Table.Rows[i]["Name"].ToString(), Table.Rows[i]["Quantity"].ToString() + " " + Table.Rows[i]["QuantityUnit"].ToString(), Table.Rows[i]["Payment"].ToString(), Table.Rows[i]["Description"].ToString(), Table.Rows[i]["ContractItemId"].ToString());
                            dataProduseContract.Enabled = false;
                        }

                    }
                }
            }

            
        }
```
  

  

The problem is allwais i have Null value in array. thanks i was able to use something similar. i have just seen online that we’re not able to extract column values for calculated columns? is there any other way of extracting this data?

query = """ query { boards (ids: %s limit: 20, page: 1) { id name columns … hatayı buldum. tablomdan 2 alan çekip value değerine yazdırmaya çalıştığım için sanırım bu hata oluştu. value: value değerini value: value.kat\_ad olarak duzeltince sorun düzeldi Check if any of the values in the cells are null.  

If they are you need to modify your code to check for null conditions before using `ToString()`. How you do this will depend on a number of factors: since you haven't tried to explain in any detail, I'll assume you know nothing, and just give you the basics.  

  

The easiest way to do this is to read the text file into a single string, and then use the .NET framework to find the match:  


```
Dim text As String = File.ReadAllText("D:\Temp\MyFile.txt")
Dim index As Integer = text.IndexOf("hello")
If index >= 0 Then
   ' String is in file, starting at character "index"
End If
```
  

There are other ways, but that is pretty much the simplest. Using [reflection](/questions/tagged/reflection "show questions tagged 'reflection'") and [expression-trees](/questions/tagged/expression-trees "show questions tagged 'expression-trees'") you can provide the parameters and then call `OrderBy` function, Instead of returning `Expression<Func<Task, T>>` and then calling `OrderBy`.


Note that `OrderBy` is an extension method and has implemented in both `System.Linq.Enumarable` and `System.Linq.Queryable` classes. The first one is for [linq-to-objects](/questions/tagged/linq-to-objects "show questions tagged 'linq-to-objects'") and the latter is for [linq-to-entities](/questions/tagged/linq-to-entities "show questions tagged 'linq-to-entities'"). [entity-framework](/questions/tagged/entity-framework "show questions tagged 'entity-framework'") needs the expression tree of the query in order to translate it to SQL commands. So we use the `Queryable` implementation.


It can be done by an extension method(explanations added as comments):



```
public static IOrderedQueryable<TSource> OrderBy<TSource>(
       this IQueryable<TSource> query, string propertyName)
{
    var entityType = typeof(TSource);

    //Create x=>x.PropName
    var propertyInfo = entityType.GetProperty(propertyName);
    ParameterExpression arg = Expression.Parameter(entityType, "x");
    MemberExpression property = Expression.Property(arg, propertyName);
    var selector = Expression.Lambda(property, new ParameterExpression[] { arg });

    //Get System.Linq.Queryable.OrderBy() method.
    var enumarableType = typeof(System.Linq.Queryable);
    var method = enumarableType.GetMethods()
         .Where(m => m.Name == "OrderBy" && m.IsGenericMethodDefinition)
         .Where(m =>
         {
            var parameters = m.GetParameters().ToList();
            //Put more restriction here to ensure selecting the right overload                
            return parameters.Count == 2;//overload that has 2 parameters
         }).Single();
    //The linq's OrderBy<TSource, TKey> has two generic types, which provided here
    MethodInfo genericMethod = method
         .MakeGenericMethod(entityType, propertyInfo.PropertyType);

    /*Call query.OrderBy(selector), with query and selector: x=> x.PropName
      Note that we pass the selector as Expression to the method and we don't compile it.
      By doing so EF can extract "order by" columns and generate SQL for it.*/
    var newQuery = (IOrderedQueryable<TSource>)genericMethod
         .Invoke(genericMethod, new object[] { query, selector });
    return newQuery;
}

```

Now you can call this overload of `OrderBy` like any other overload of it.  

For example:



```
var cheapestItems = _context.Items.OrderBy("Money").Take(10).ToList();

```

Which translates to:



```
SELECT TOP (10)  {coulmn names} FROM  [dbo].[Items] AS [Extent1] 
       ORDER BY [Extent1].[Money] ASC

```

This approach can be used to define all overloads of `OrderBy` and `OrderByDescending` methods to have `string` property selector. [@assetsoft](/u/assetsoft),

check this xaml, used linq query inside invoke code.

it will return list(of list(of fileinfo)), so you can merger the files by lists

[splitfilesbasedonsize.xaml](/uploads/short-url/qdrm6cup1a9ykmbpc4elbomg5ga.xaml) (9.4 kb)