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How can you remove columns from the CExtTreeGridWnd?
Regards,
Eddie

The CExtGridWnd::ColumnRemove() method removes a column(s) both from CExtGridWnd and CExtTreeGridWnd controls.

When ever I try that I get an assert from the following location:
bool CExtTreeGridDataProvider::ColumnRemove(
    ULONG nColNo,
    ULONG nRemoveCount // = 1
    )
{
    ASSERT_VALID( this );
    nColNo;
    nRemoveCount;
    // this method must never be invoked
    ASSERT( FALSE );
    return false;
}

Not it’s understandable what you want. The CExtTreeGridDataProvider::ColumnRemove() method should redirect its call to the internall cache data provider as it is done in the CExtTreeGridDataProvider::ColumnInsert() method:

bool CExtTreeGridDataProvider::ColumnRemove(
    ULONG nColNo,
    ULONG nRemoveCount // = 1
    )
{
    ASSERT_VALID( this );
CExtGridDataProvider & _DP = _Tree_GetCacheDP();
    return _DP.ColumnRemove( _Tree_MapColToCache( nColNo ), nRemoveCount );
}

I have changed the CExtTreeGridDataProvider to the below in the library and rebuilt it and ColumnRemoveAll( false ); seems to work now.
bool CExtTreeGridDataProvider::ColumnRemove(
    ULONG nColNo,
    ULONG nRemoveCount // = 1
    )
{
    //ASSERT_VALID( this );
    //nColNo;
    //nRemoveCount;
    //// this method must never be invoked
    //ASSERT( FALSE );
    //return false;
    CExtGridDataProvider & _DP = _Tree_GetCacheDP();
    return _DP.ColumnRemove( _Tree_MapColToCache( nColNo ), nRemoveCount );
}