Deserialization failed: The 'DataType' attribute is not declared

I faced the above problem when I tried to open a report in Visual Studio 2008. I had edited the report many times in the past and I don’t know what caused the problem. In my opinion it must be a bug of the report builder of Visual Studio 2008. I opened the xml definition of the report and compared it with a version of the report witch was working. The difference can be found below.

Working xml

      <ValidValues>

        <ParameterValues>

          <ParameterValue>

            <Value>-1</Value>

            <Label>Less Than</Label>

          </ParameterValue>

          <ParameterValue>

            <Value>0</Value>

            <Label>Equal</Label>

          </ParameterValue>

          <ParameterValue>

            <Value>1Value>

            <Label>Greater Than</Label>

          </ParameterValue>

        </ParameterValues>

      </ValidValues>

Not working xml

      <ValidValues>

        <ParameterValues>

          <ParameterValue>

            <Value DataType="Integer">-1</Value>

            <Label>Less Than</Label>

          </ParameterValue>

          <ParameterValue>

            <Value DataType="Integer">0</Value>

            <Label>Equal</Label>

          </ParameterValue>

          <ParameterValue>

            <Value DataType="Integer">1</Value>

            <Label>Greater Than</Label>

          </ParameterValue>

        </ParameterValues>

      </ValidValues>

I removed the DataType attribute and everything worked fine