这是 MFC C++ 中单个 select 组合框的事件处理程序

Question

我在选择特定组合框时启用或禁用某些文本框时遇到问题。

我试过使用 OnCbnSelChangeLvLayers() 和 OnCbnDropdownLvLayers()。第一个事件处理程序的问题是我必须两次单击相同的值并且组合框中的选择冻结。第二个事件处理程序解决了冻结问题，但我必须单击组合框的下拉菜单才能使事件发生。我还为组合框尝试了一些其他事件处理程序，但没有成功。 m_d_layers 是组合框选择的字符串变量 (1,2,3,4)

DDX:

void CThermalToolDlg::DoDataExchange(CDataExchange* pDX)
{
    DDX_CBString(pDX, IDC_LV_LAYERS, m_d_lvlayers);
}

消息映射：

BEGIN_MESSAGE_MAP(CThermalToolDlg, CDialogEx)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_CBN_DROPDOWN(IDC_LV_LAYERS, &CThermalToolDlg::OnCbnDropdownLvLayers)
ON_CBN_DROPDOWN(IDC_HV_LAYERS, &CThermalToolDlg::OnCbnDropdownHvLayers)
ON_CBN_DROPDOWN(IDC_LVDUCTTYPE1, &CThermalToolDlg::OnCbnDropdownLvducttype1)
ON_CBN_DROPDOWN(IDC_LVDUCTTYPE2, &CThermalToolDlg::OnCbnDropdownLvducttype2)
ON_CBN_DROPDOWN(IDC_LVDUCTTYPE3, &CThermalToolDlg::OnCbnDropdownLvducttype3)
ON_CBN_DROPDOWN(IDC_HVDUCTTYPE1, &CThermalToolDlg::OnCbnDropdownHvducttype1)
ON_CBN_DROPDOWN(IDC_HVDUCTTYPE2, &CThermalToolDlg::OnCbnDropdownHvducttype2)
ON_CBN_DROPDOWN(IDC_HVDUCTTYPE3, &CThermalToolDlg::OnCbnDropdownHvducttype3)
ON_BN_CLICKED(IDCANCEL, &CThermalToolDlg::OnBnClickedCancel)
ON_BN_CLICKED(ID_CALCULATE, &CThermalToolDlg::OnCalculate)
//ON_CBN_EDITUPDATE(IDC_LV_LAYERS,&CThermalToolDlg::OnCbnEditupdateLvLayers)
//ON_CBN_SELENDOK(IDC_LV_LAYERS, &CThermalToolDlg::OnCbnSelendokLvLayers)

END_MESSAGE_MAP()

事件处理程序：

void CThermalToolDlg::OnCbnDropdownLvLayers()
{
    // TODO: Add your control notification handler code here
    UpdateData();

    if (m_d_lvlayers == "1")
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(0);
            //and so on
    }
    else if (m_d_lvlayers == "2")
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(1);
            //and so on

    }
    else if (m_d_lvlayers == "3")
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(1);
            //and so on
    }
    else
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(1);
            //and so on
    }
}

我想在不冻结组合框的情况下通过一次单击获得所需的 enabling/disabling。有没有其他方法或更快的方法？

Answer 1

这似乎是 drop-list 组合框和简单组合框（不是 drop-down）的错误。 DDX_CBString 或 DDX_CBStringExact 未检索到正确的值以响应 ON_CBN_DROPDOWN。

您可以使用自己的代码检索正确的字符串：

void CThermalToolDlg::OnCbnDropdownLvLayers() 
{ 
    //UpdateData();
    CComboBox *cb = (CComboBox*)GetDlgItem(IDC_LV_LAYERS);
    if(cb)
    {
        int sel = cb->GetCurSel();
        if(sel >= 0)
            cb->GetLBText(sel, m_d_lvlayers);
    }
    TRACE(L"%s\n", m_d_lvlayers.GetString());
}

出于调试目的，注释掉 ON_CBN_DROPDOWN(IDC_LV_LAYERS...) 以外的其他消息。在继续之前确保您有正确的字符串。

不要像您在上一个问题中所做的那样调用 UpdateData(FALSE)。如果未检索到正确的字符串，这可能会导致问题。

Answer 2

多亏了@BarmakShemirani，我在 ON_CBN_SELENDOK 事件处理程序中使用了他检索正确字符串的代码而不是 UpdateData()，现在它就像一个魅力

DDX:

void CThermalToolDlg::DoDataExchange(CDataExchange* pDX)
{
  DDX_CBString(pDX, IDC_LV_LAYERS, m_d_lvlayers);
}

消息映射：

BEGIN_MESSAGE_MAP(CThermalToolDlg, CDialogEx)
ON_WM_PAINT()
ON_WM_QUERYDRAGICON()
ON_CBN_SELENDOK(IDC_LV_LAYERS, &CThermalToolDlg::OnCbnSelendokLvLayers)
ON_BN_CLICKED(IDCANCEL, &CThermalToolDlg::OnBnClickedCancel)
ON_BN_CLICKED(ID_CALCULATE, &CThermalToolDlg::OnCalculate)
END_MESSAGE_MAP()

事件处理程序：

void CThermalToolDlg::OnCbnSelendokLvLayers()
{
    // TODO: Add your control notification handler code here
    CComboBox *cb = (CComboBox*)GetDlgItem(IDC_LV_LAYERS);
    if (cb)
    {
        int sel = cb->GetCurSel();
        if (sel >= 0)
            cb->GetLBText(sel, m_d_lvlayers);
    }
    TRACE(_T("[%s]\n"), m_d_lvlayers.GetString());

    /*UpdateData();*/

    if (m_d_lvlayers == "1")
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(0);
        GetDlgItem(IDC_LV2_PC)->EnableWindow(0);
        GetDlgItem(IDC_LV2_RESIN)->EnableWindow(0);
        GetDlgItem(IDC_LV2_RESO)->EnableWindow(0);
        GetDlgItem(IDC_LV2_INST)->EnableWindow(0);
        GetDlgItem(IDC_LV3_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV3_ICI)->EnableWindow(0);
        GetDlgItem(IDC_LV3_PC)->EnableWindow(0);
        GetDlgItem(IDC_LV3_RESIN)->EnableWindow(0);
        GetDlgItem(IDC_LV3_RESO)->EnableWindow(0);
        GetDlgItem(IDC_LV3_INST)->EnableWindow(0);
        GetDlgItem(IDC_LV4_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV4_ICI)->EnableWindow(0);
        GetDlgItem(IDC_LV4_PC)->EnableWindow(0);
        GetDlgItem(IDC_LV4_RESIN)->EnableWindow(0);
        GetDlgItem(IDC_LV4_RESO)->EnableWindow(0);
        GetDlgItem(IDC_LV4_INST)->EnableWindow(0);
        GetDlgItem(IDC_LVDUCTTYPE1)->EnableWindow(0);
        GetDlgItem(IDC_LVDUCTTYPE2)->EnableWindow(0);
        GetDlgItem(IDC_LVDUCTTYPE3)->EnableWindow(0);
        GetDlgItem(IDC_LV_D_NO_12)->EnableWindow(0);
        GetDlgItem(IDC_LV_D_NO_23)->EnableWindow(0);
        GetDlgItem(IDC_LV_D_NO_34)->EnableWindow(0);
    }
    else if (m_d_lvlayers == "2")
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(1);
        GetDlgItem(IDC_LV2_PC)->EnableWindow(1);
        GetDlgItem(IDC_LV2_RESIN)->EnableWindow(1);
        GetDlgItem(IDC_LV2_RESO)->EnableWindow(1);
        GetDlgItem(IDC_LV2_INST)->EnableWindow(1);
        GetDlgItem(IDC_LV3_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV3_ICI)->EnableWindow(0);
        GetDlgItem(IDC_LV3_PC)->EnableWindow(0);
        GetDlgItem(IDC_LV3_RESIN)->EnableWindow(0);
        GetDlgItem(IDC_LV3_RESO)->EnableWindow(0);
        GetDlgItem(IDC_LV3_INST)->EnableWindow(0);
        GetDlgItem(IDC_LV4_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV4_ICI)->EnableWindow(0);
        GetDlgItem(IDC_LV4_PC)->EnableWindow(0);
        GetDlgItem(IDC_LV4_RESIN)->EnableWindow(0);
        GetDlgItem(IDC_LV4_RESO)->EnableWindow(0);
        GetDlgItem(IDC_LV4_INST)->EnableWindow(0);
        GetDlgItem(IDC_LVDUCTTYPE1)->EnableWindow(1);
        GetDlgItem(IDC_LVDUCTTYPE2)->EnableWindow(0);
        GetDlgItem(IDC_LVDUCTTYPE3)->EnableWindow(0);
        GetDlgItem(IDC_LV_D_NO_12)->EnableWindow(1);
        GetDlgItem(IDC_LV_D_NO_23)->EnableWindow(0);
        GetDlgItem(IDC_LV_D_NO_34)->EnableWindow(0);
    }
    else if (m_d_lvlayers == "3")
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(1);
        GetDlgItem(IDC_LV2_PC)->EnableWindow(1);
        GetDlgItem(IDC_LV2_RESIN)->EnableWindow(1);
        GetDlgItem(IDC_LV2_RESO)->EnableWindow(1);
        GetDlgItem(IDC_LV2_INST)->EnableWindow(1);
        GetDlgItem(IDC_LV3_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV3_ICI)->EnableWindow(1);
        GetDlgItem(IDC_LV3_PC)->EnableWindow(1);
        GetDlgItem(IDC_LV3_RESIN)->EnableWindow(1);
        GetDlgItem(IDC_LV3_RESO)->EnableWindow(1);
        GetDlgItem(IDC_LV3_INST)->EnableWindow(1);
        GetDlgItem(IDC_LV4_CU)->EnableWindow(0);
        GetDlgItem(IDC_LV4_ICI)->EnableWindow(0);
        GetDlgItem(IDC_LV4_PC)->EnableWindow(0);
        GetDlgItem(IDC_LV4_RESIN)->EnableWindow(0);
        GetDlgItem(IDC_LV4_RESO)->EnableWindow(0);
        GetDlgItem(IDC_LV4_INST)->EnableWindow(0);
        GetDlgItem(IDC_LVDUCTTYPE1)->EnableWindow(1);
        GetDlgItem(IDC_LVDUCTTYPE2)->EnableWindow(1);
        GetDlgItem(IDC_LVDUCTTYPE3)->EnableWindow(0);
        GetDlgItem(IDC_LV_D_NO_12)->EnableWindow(1);
        GetDlgItem(IDC_LV_D_NO_23)->EnableWindow(1);
        GetDlgItem(IDC_LV_D_NO_34)->EnableWindow(0);
    }
    else
    {
        GetDlgItem(IDC_LV2_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV2_ICI)->EnableWindow(1);
        GetDlgItem(IDC_LV2_PC)->EnableWindow(1);
        GetDlgItem(IDC_LV2_RESIN)->EnableWindow(1);
        GetDlgItem(IDC_LV2_RESO)->EnableWindow(1);
        GetDlgItem(IDC_LV2_INST)->EnableWindow(1);
        GetDlgItem(IDC_LV3_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV3_ICI)->EnableWindow(1);
        GetDlgItem(IDC_LV3_PC)->EnableWindow(1);
        GetDlgItem(IDC_LV3_RESIN)->EnableWindow(1);
        GetDlgItem(IDC_LV3_RESO)->EnableWindow(1);
        GetDlgItem(IDC_LV3_INST)->EnableWindow(1);
        GetDlgItem(IDC_LV4_CU)->EnableWindow(1);
        GetDlgItem(IDC_LV4_ICI)->EnableWindow(1);
        GetDlgItem(IDC_LV4_PC)->EnableWindow(1);
        GetDlgItem(IDC_LV4_RESIN)->EnableWindow(1);
        GetDlgItem(IDC_LV4_RESO)->EnableWindow(1);
        GetDlgItem(IDC_LV4_INST)->EnableWindow(1);
        GetDlgItem(IDC_LVDUCTTYPE1)->EnableWindow(1);
        GetDlgItem(IDC_LVDUCTTYPE2)->EnableWindow(1);
        GetDlgItem(IDC_LVDUCTTYPE3)->EnableWindow(1);
        GetDlgItem(IDC_LV_D_NO_12)->EnableWindow(1);
        GetDlgItem(IDC_LV_D_NO_23)->EnableWindow(1);
        GetDlgItem(IDC_LV_D_NO_34)->EnableWindow(1);
    }
}

谢谢大家！

这是 MFC C++ 中单个 select 组合框的事件处理程序

Which is the event handler for Combobox for single select in MFC C++

c++

mfc

visual-studio