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Cannot Figure out how to add an Order By statement to a LINQ query

Posted on 2014-01-29
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Last Modified: 2016-02-10
Hello.
So, I have this Linq query that works well:

Dim listOfFiles = (From sfn In xdoc.Descendants("File") _
                   Where sfn.Attribute("FileName").Value.ToLower().Contains(searchKey) _
                   Select New With _
                   { _
                       .FileName = sfn.Attribute("FileName"), _
                       .FolderAncestors = sfn.Ancestors("Folder").Aggregate("", Function(path As String, current As XElement) current.Attribute("FolderName").Value & "\" & path)_
                  }).ToList()

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I cannot figure out how to do Order By FolderAncestors.

The XML File has the following structure (if that help)

<?xml version="1.0" encoding="utf-8"?>
<Folders xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" FolderName="myTestFdv" FolderCreatedOn="3/2/2013 1:58:35 AM" FolderId="0f828a3a-b361-480c-982c-db4f92d7bb9b">
  <FolderList>
    <Folder FolderName="12345" FolderCreatedOn="3/13/2013 12:25:41 AM" FolderId="fe261d0e-7ca8-4a65-bad0-df9eed59bfc0">
      <FolderList>
        <Folder FolderName="images" FolderCreatedOn="3/13/2013 12:25:41 AM" FolderId="fa9932e1-0ea9-4eef-bd61-4d9e1717fa72">
          <FolderList>
            <Folder FolderName="icons" FolderCreatedOn="3/13/2013 12:25:41 AM" FolderId="79b240d4-6e49-49e0-a569-be667376acbc">
              <FolderList />
              <FileList>
                <File FileName="accdb.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="584322_accdb.jpg" Size="927" />
                <File FileName="bmp.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="338435_bmp.jpg" Size="276" />
                <File FileName="docx.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="428127_docx.jpg" Size="932" />
                <File FileName="gif.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="995346_gif.jpg" Size="822" />
                <File FileName="jpg.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="40293_jpg.jpg" Size="818" />
                <File FileName="png.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="607512_png.jpg" Size="893" />
                <File FileName="pptx.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="174831_pptx.jpg" Size="927" />
                <File FileName="psd.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="742050_psd.jpg" Size="809" />
                <File FileName="tif.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="786896_tif.jpg" Size="768" />
                <File FileName="txt.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="354216_txt.jpg" Size="506" />
                <File FileName="xlsx.gif" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="921434_xlsx.jpg" Size="949" />
              </FileList>
            </Folder>
            <Folder FolderName="thumbnails" FolderCreatedOn="3/13/2013 12:25:41 AM" FolderId="f19b98a3-f76c-4c10-a6c0-b6fd903c4080">
              <FolderList />
              <FileList>
                <File FileName="570153_Untitled.jpg" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="488754_570153_Untitled.jpg" Size="1012" />
                <File FileName="60259_yellow.jpg" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="578446_60259_yellow.jpg" Size="1946" />
                <File FileName="884076_Untitled.jpg" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="145766_884076_Untitled.jpg" Size="1009" />
                <File FileName="941401_photoshop1.jpg" FileCreatedOn="3/13/2013 12:25:41 AM" FileUpdatedOn="3/13/2013 12:25:41 AM" FileType="image" Thumbnail="712985_941401_photoshop1.jpg" Size="228" />
              </FileList>
            </Folder>
          </FolderList>
          <FileList />
        </Folder>
      </FolderList>
      <FileList />
    </Folder>
    <Folder FolderName="Subfolder1" FolderCreatedOn="3/2/2013 1:58:48 AM" FolderId="7e21b53b-8ff2-45e9-8e11-20dcdd0b9dde">
      <FolderList>
        <Folder FolderName="SubSubFolder1_1" FolderCreatedOn="3/3/2013 9:35:47 PM" FolderId="bf7812df-c98f-4f0e-b348-a2a1eb9d99ef">
          <FolderList />
          <FileList>
            <File FileName="ExcelWorksheet.xlsx" FileCreatedOn="3/3/2013 9:36:01 PM" FileUpdatedOn="3/3/2013 9:36:01 PM" FileType="file" Size="8746" />
          </FileList>
        </Folder>
      </FolderList>
      <FileList />
    </Folder>
    <Folder FolderName="Subfolder2" FolderCreatedOn="3/2/2013 1:58:51 AM" FolderId="015b93c2-9324-46fd-8a0c-8a8a9ecc10a1">
      <FolderList />
      <FileList>
        <File FileName="PPPresentation.pptx" FileCreatedOn="3/2/2013 1:59:19 AM" FileUpdatedOn="3/2/2013 1:59:19 AM" FileType="file" Size="27140" />
        <File FileName="Untitled.jpg" FileCreatedOn="3/7/2013 9:31:59 PM" FileUpdatedOn="3/7/2013 9:31:59 PM" FileType="image" Thumbnail="639073_Untitled.jpg" Size="45956" />
      </FileList>
    </Folder>
    <Folder FolderName="Subfolder3" FolderCreatedOn="3/2/2013 1:58:53 AM" FolderId="f5f20a02-5c27-4e13-a63f-86173431b12b">
      <FolderList>
        <Folder FolderName="SubSubFolder3_1" FolderCreatedOn="3/2/2013 2:05:30 AM" FolderId="f95411b4-47b8-4261-8a2c-9101dc7a6acf">
          <FolderList />
          <FileList />
        </Folder>
        <Folder FolderName="SubSubFolder3_2" FolderCreatedOn="3/2/2013 2:05:33 AM" FolderId="552f12cd-d3d7-49b6-8a4d-f453ae5efb54">
          <FolderList />
          <FileList>
            <File FileName="New Microsoft Access Database.accdb" FileCreatedOn="3/2/2013 2:05:42 AM" FileUpdatedOn="3/2/2013 2:05:42 AM" FileType="file" Size="495616" />
            <File FileName="New Microsoft Excel Worksheet.xlsx" FileCreatedOn="3/2/2013 2:05:46 AM" FileUpdatedOn="3/2/2013 2:05:46 AM" FileType="file" Size="8746" />
            <File FileName="Untitled.bmp" FileCreatedOn="3/7/2013 9:31:33 PM" FileUpdatedOn="3/7/2013 9:31:34 PM" FileType="image" Thumbnail="87635_Untitled.jpg" Size="2239542" />
            <File FileName="yellow.tif" FileCreatedOn="3/8/2013 7:35:36 PM" FileUpdatedOn="3/8/2013 7:35:39 PM" FileType="image" Thumbnail="392459_yellow.jpg" Size="144078324" />
          </FileList>
        </Folder>
      </FolderList>
      <FileList />
    </Folder>
    <Folder FolderName="Subfolder4" FolderCreatedOn="3/2/2013 1:58:59 AM" FolderId="05e39966-9661-493c-80a2-be7dff925828">
      <FolderList />
      <FileList>
        <File FileName="photoshop1.png" FileCreatedOn="3/7/2013 10:11:05 PM" FileUpdatedOn="3/7/2013 10:11:08 PM" FileType="image" Thumbnail="796074_photoshop1.jpg" Size="4760" />
        <File FileName="photoshop1.psd" FileCreatedOn="3/7/2013 10:07:32 PM" FileUpdatedOn="3/7/2013 10:07:32 PM" FileType="file" Size="47654" />
      </FileList>
    </Folder>
    <Folder FolderName="Subfolder5" FolderCreatedOn="3/2/2013 1:58:56 AM" FolderId="5d3e48b3-ecb1-4ec1-b52c-e45bc3dd9c59">
      <FolderList />
      <FileList>
        <File FileName="myAccessDatabase.accdb" FileCreatedOn="3/2/2013 1:59:37 AM" FileUpdatedOn="3/2/2013 1:59:37 AM" FileType="file" Size="495616" />
        <File FileName="myTextDocument.txt" FileCreatedOn="3/2/2013 1:59:41 AM" FileUpdatedOn="3/2/2013 1:59:41 AM" FileType="file" Size="0" />
      </FileList>
    </Folder>
    <Folder FolderName="Subfolder6" FolderCreatedOn="3/5/2013 10:49:08 PM" FolderId="96fd5601-d0ad-4b71-b05a-a9272b440fa3">
      <FolderList />
      <FileList>
        <File FileName="Untitled.png" FileCreatedOn="3/7/2013 9:31:17 PM" FileUpdatedOn="3/7/2013 9:31:17 PM" FileType="image" Thumbnail="379174_Untitled.jpg" Size="33093" />
      </FileList>
    </Folder>
    <Folder FolderName="Subfolder7" FolderCreatedOn="3/5/2013 10:49:19 PM" FolderId="9812d6e3-e535-4ea0-8715-b0f3fc1efaeb">
      <FolderList />
      <FileList />
    </Folder>
  </FolderList>
  <FileList>
    <File FileName="MyRootTextDocument.txt" FileCreatedOn="3/2/2013 1:59:08 AM" FileUpdatedOn="3/2/2013 1:59:08 AM" FileType="file" Size="0" />
    <File FileName="MyRootWordDocument.docx" FileCreatedOn="3/2/2013 1:59:03 AM" FileUpdatedOn="3/2/2013 1:59:03 AM" FileType="file" Size="0" />
  </FileList>
</Folders>

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P.S.  Also, how can I dynamically change the order by clause? Or the Where clause for that matter.
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Comment
Question by:vituxa
  • 2
3 Comments
 
LVL 21

Accepted Solution

by:
Craig Wagner earned 500 total points
ID: 39819541
To sort just add a call to .OrderBy() before you do the ToList().

        Dim listOfFiles = (From sfn In xdoc.Descendants("File") _
                   Where sfn.Attribute("FileName").Value.ToLower().Contains(searchKey) _
                   Select New With _
                   { _
                       .FileName = sfn.Attribute("FileName"), _
                       .FolderAncestors = sfn.Ancestors("Folder").Aggregate("", Function(path As String, current As XElement) current.Attribute("FolderName").Value & "\" & path) _
                  }).OrderBy(Function(sfn) sfn.FileName).ToList()

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If you want to supply the Where and Order criteria at run time you'd be better off to switch to the lambda syntax. Then you can pass in the lambda's as run-time parameters.

' With hard-coded Where() and OrderBy()

        Dim listOfFiles = xdoc.Descendants("File") _
            .Where(Function(sfn) sfn.Attribute("FileName").Value.ToLower().Contains(searchKey)) _
            .Select(Function(sfn) New With _
            { _
                .FileName = sfn.Attribute("FileName"), _
                .FolderAncestors = sfn.Ancestors("Folder").Aggregate("", Function(path As String, current As XElement) current.Attribute("FolderName").Value & "\" & path) _
            }) _
            .OrderBy(Function(sfn) sfn.FileName) _
            .ToList()


' With run-time provided Where() and OrderBy()

        Dim listOfFiles = xdoc.Descendants("File") _
            .Where(myWhereCriteria) _
            .Select(Function(sfn) New With _
            { _
                .FileName = sfn.Attribute("FileName"), _
                .FolderAncestors = sfn.Ancestors("Folder").Aggregate("", Function(path As String, current As XElement) current.Attribute("FolderName").Value & "\" & path) _
            }) _
            .OrderBy(myOrderByCriteria) _
            .ToList()

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0
 
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Author Comment

by:vituxa
ID: 39819754
I am sorry, can you please give me an example of what myOrderByCriteria and myWhereCriteria would be, and what would it look like if there are multiple where and order by criterias?
0
 
LVL 1

Author Closing Comment

by:vituxa
ID: 39819755
Thank you so much, can you please answer my question above?
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