c++ IntelliSense: expression must be a modifiable lvalue

Question

im getting these two errors

1>c:\users\owner\documents\visual studio 2010\projects\monopoly\monopoly\xfileentity.cpp(376): error C3490: 'pDrawMesh' cannot be modified because it is being accessed through a const object
IntelliSense: expression must be a modifiable lvalue

i declared pDrawMesh in my class than used it in one function.
here is my class

class CXFileEntity
{
        ......
 LPD3DXMESH pDrawMesh;
        .....
};

here is where i used the variable

void CXFileEntity::DrawMeshContainer(LPD3DXMESHCONTAINER meshContainerBase, LPD3DXFRAME frameBase) const
{
 // Cast to our extended frame type
 D3DXFRAME_EXTENDED *frame = (D3DXFRAME_EXTENDED*)frameBase;  

 // Cast to our extended mesh container
 D3DXMESHCONTAINER_EXTENDED *meshContainer = (D3DXMESHCONTAINER_EXTENDED*)meshContainerBase;

 // Set the world transform But only if it is not a skinned mesh. 
 // The skinned mesh has the transform built in (the vertices are already transformed into world space) so we set identity
 // Added 24/08/10
 if (meshContainer->pSkinInfo)
 {
  D3DXMATRIX mat;
  D3DXMatrixIdentity(&mat);
  m_d3dDevice->SetTransform(D3DTS_WORLD, &mat);
 }
 else
  m_d3dDevice->SetTransform(D3DTS_WORLD, &frame->exCombinedTransformationMatrix);


 // Loop through all the materials in the mesh rendering each subset
 for (unsigned int iMaterial = 0; iMaterial < meshContainer->NumMaterials; iMaterial++)
 {
  // use the material in our extended data rather than the one in meshContainer->pMaterials[iMaterial].MatD3D
  m_d3dDevice->SetMaterial( &meshContainer->exMaterials[iMaterial] );
  m_d3dDevice->SetTexture( 0, meshContainer->exTextures[iMaterial] );

  // Select the mesh to draw, if there is skin then use the skinned mesh else the normal one
  pDrawMesh = (meshContainer->pSkinInfo) ? meshContainer->exSkinMesh: meshContainer->MeshData.pMesh;

  // Finally Call the mesh draw function
  pDrawMesh->DrawSubset(iMaterial);
 }
}

Answer 1

Your member function is const-qualified. You cannot modify any member variables from within a const-qualified member function unless they are declared mutable.

You need to make pDrawMesh mutable, remove the const-qualification from DrawMeshContainer, or find some other way to accomplish whatever it is you are trying to accomplish.