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POLink OrderBy method not taking effect after Union method
 

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  1. POLink OrderBy method not taking effect after Union method
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    <p>I'm using LINQ's Union method to combine two or more collections. After that I'm trying to apply sorting to the combined collection by calling OrderBy on a field that is common to the collections. Here is how I am applying sorting:</p> <pre><code>combinedCollection.OrderBy(row =&gt; row["common_field"]); </code></pre> <p>combinedCollection is defined as:</p> <pre><code>Enumerable&lt;DataRow&gt; combinedCollection; </code></pre> <p>I need the sorting to be applied to the entire combined collection. For some reason, that is not happening. Instead I see there is sorting applied on some other field separately within each 'collection' block within the combined collection</p> <p>And idea why??</p> <h1>First Edit</h1> <pre><code>foreach (....) { if (combinedCollection != null) { combinedCollection = combinedCollection.Union(aCollection); } else { combinedCollection = aCollection; } } </code></pre> <h1>Second Edit</h1> <pre><code> _Cmd.CommandText = "SELECT Person.Contact.FirstName, Person.Contact.LastName, Person.Address.City, DATEDIFF(YY, HumanResources.Employee.BirthDate, GETDATE()) AS Age" + " FROM HumanResources.EmployeeAddress INNER JOIN" + " HumanResources.Employee ON HumanResources.EmployeeAddress.EmployeeID = HumanResources.Employee.EmployeeID INNER JOIN" + " Person.Address ON HumanResources.EmployeeAddress.AddressID = Person.Address.AddressID INNER JOIN" + " Person.Contact ON HumanResources.Employee.ContactID = Person.Contact.ContactID AND HumanResources.Employee.ContactID = Person.Contact.ContactID AND " + " HumanResources.Employee.ContactID = Person.Contact.ContactID AND HumanResources.Employee.ContactID = Person.Contact.ContactID"; DataTable employeeTable = new DataTable(); _Adpt.Fill(employeeTable); DataRow[] allRows = null; allRows = employeeTable.Select(""); IEnumerable&lt;DataRow&gt; filteredEmployeeRows; filteredEmployeeRows = from row in allRows select row; // Declare a variable to hold the city-filtered rows and set it to null for now IEnumerable&lt;DataRow&gt; cityFilteredEmployeeRows = null; //Copy filtered rows into a data table DataTable filteredEmployeeTable = filteredEmployeeRows.CopyToDataTable&lt;DataRow&gt;(); foreach (DataRowView city in CityListBox.SelectedItems) { // create an exact copy of the data table DataTable filteredEmployeeCopyTable = filteredEmployeeTable.Copy(); // Enumerate it IEnumerable&lt;DataRow&gt; filteredEmployeeRowsInSingleCity = filteredEmployeeCopyTable.AsEnumerable(); // Apply the city filter filteredEmployeeRowsInSingleCity = _ApplyCityFilter(filteredEmployeeRowsInSingleCity, city["City"].ToString()); if (cityFilteredEmployeeRows != null) { // Combine the filtered rows for this city with the overall collection of rows cityFilteredEmployeeRows = cityFilteredEmployeeRows.Union(filteredEmployeeRowsInSingleCity); } else { cityFilteredEmployeeRows = filteredEmployeeRowsInSingleCity; } } //apply ordering cityFilteredEmployeeRows.OrderBy(row =&gt; row["Age"]); //cityFilteredEmployeeRows.OrderByDescending(row =&gt; row["Age"]); EmployeeGridView.DataSource = cityFilteredEmployeeRows.CopyToDataTable&lt;DataRow&gt;(); </code></pre> <p>.......</p> <pre><code>private IEnumerable&lt;DataRow&gt; _ApplyCityFilter(IEnumerable&lt;DataRow&gt; filteredEmployeeRows, string city) { IEnumerable&lt;DataRow&gt; temp = filteredEmployeeRows; filteredEmployeeRows = from row in temp where row["City"].ToString() == city select row; return filteredEmployeeRows; } </code></pre>
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    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. USYosief Kesete
    1. USYosief Kesete
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    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
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      1. PTAnswer
    1. This table or related slice is empty.
    1. COHow you combine collections, show code snippet.
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      1. POLink OrderBy method not taking effect after Union method
      1. USHamlet Hakobyan
    2. COHi Hamlet, please see under section 'First Edit'
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      1. POLink OrderBy method not taking effect after Union method
      1. USYosief Kesete
    3. CONot the issue but what you want is Concat.
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      1. POLink OrderBy method not taking effect after Union method
      1. USusr
 

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