can .webpart be converted to .dwp?

Question

Is it possible to convert any .webpart file to a .dwp so that I would

1. Export a .webpart file
2. Convert it to .dwp file (add every property in dwp format)
3. Import it back

Answer 1

Since .dwp web part file corresponds to SharePoint-based web parts and .webpart to ASP.NET web parts, web part file can not be converted without rebuilding web parts itself.

The difference between SharePoint-based and ASP.NET web parts

The set of features provided exclusively by Microsoft.SharePoint.WebPartPages.WebPart is as follows:

• Cross page connections
• Connections between Web Parts that are outside of a zone
• Client-side connections (Web Part Page Services Component)
• Data caching infrastructure, including the ability to cache to the database

Example: convert Content Editor web part file format (V2 -> V3)

An attempt to convert SharePoint-based web part file from version 2 (MSContentEditror.dwp):

<?xml version="1.0" encoding="utf-8"?>
<WebPart xmlns="http://schemas.microsoft.com/WebPart/v2">
    <Assembly>Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c</Assembly>
    <TypeName>Microsoft.SharePoint.WebPartPages.ContentEditorWebPart</TypeName>
    <Title>Content Editor</Title>
    <Description>Allows authors to enter rich text content.</Description>
    <PartImageLarge>/_layouts/images/mscontl.gif</PartImageLarge>
</WebPart>

to version 3 (MSContentEditror.webpart):

<?xml version="1.0" encoding="utf-8"?>
<webParts>
  <webPart xmlns="http://schemas.microsoft.com/WebPart/v3">
    <metaData>
      <type name="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c,Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" />
      <importErrorMessage>Cannot import this Web Part.</importErrorMessage>
    </metaData>
    <data>
      <properties>
        <property name="Title">Content Editor</property>
        <property name="Description">Allows authors to enter rich text content.</property>
        <property name="PartImageLarge">/_layouts/images/mscontl.gif</property>
      </properties>
    </data>
  </webPart>
</webParts>

will give an error during adding web part on page.