MaterialDesign OpenDialogCommand不生效

只需要将 Button 放 置在 DialogHost:内即可：

     <materialDesign:DialogHost Grid.Column="2">
                            <Button Command="{x:Static materialDesign:DialogHost.OpenDialogCommand}">
                                <Button.CommandParameter>
                                    <StackPanel Margin="16">
                                        <ProgressBar Style="{DynamicResource MaterialDesignCircularProgressBar}"
                                                     HorizontalAlignment="Center" Margin="16" IsIndeterminate="True"
                                                     Value="0" />
                                        <Button IsCancel="True" Margin="8 0 0 0"
                                                Command="{x:Static materialDesign:DialogHost.CloseDialogCommand}"
                                                Content="Save" />
                                    </StackPanel>
                                </Button.CommandParameter>
                                Edit
                            </Button>
                        </materialDesign:DialogHost>