Question

我在按下winforms应用程序上的按钮时尝试显示一个消息框，但MessageBox挂起并且永远不会返回值。

private void btnApply_Click(object sender, EventArgs e)
    {
        bool current = false;
        if (cmbEmergencyLandingMode.SelectedIndex > 0)
        {
            if (m_WantedData != false)
            {
                DialogResult dr = MessageBox.Show("Are you sure you want to enable Emergency Landing mode?", "Warning!", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);

                //i never get to this point
                current = (dr == DialogResult.Yes);
            }
        }

        if (m_WantedData == current)
        {
            //do something
        }
        else if (m_WantedData != null)
        { 
            //do something else
        }
    }

编辑： 好的，所以我通过处理后台工作人员的按钮事件让它工作：

private void btnApply_Click(object sender, EventArgs e)
    {
        if (!bwApply.IsBusy) 
            bwApply.RunWorkerAsync(cmbEmergencyLandingMode.SelectedIndex);
    }

    void bwApply_DoWork(object sender, DoWorkEventArgs e)
    {
        bool current = false;
        int selectedIndex = (int)e.Argument;

        if (selectedIndex > 0)
        {
            if (m_WantedData != false)
            {
                DialogResult dr = MessageBox.Show(
                    "Are you sure you want to enable Emergency Landing mode?",
                    "Warning!", MessageBoxButtons.YesNo, MessageBoxIcon.Warning);
                current = (dr == DialogResult.Yes);
            }
        }

        if (m_WantedData == current)
        {
            //do something
        }
        else if (m_WantedData != null)
        {
            //do something else
        }
    }

感谢所有帮助过的人！

Answer 1

您是否尝试过指定消息框所有者，如下所示？

DialogResult dr = MessageBox.Show(
    this,
    "Are you sure you want to enable Emergency Landing mode?",
    "Warning!",
    MessageBoxButtons.YesNo,
    MessageBoxIcon.Warning);

如果在消息框后面的UI发生并发更改时显示消息框，我发现应用程序的行为与此类似。如果上述方法没有帮助，请尝试通过异步处理事件来减轻UI处理（即WinAPI消息传递）的压力，如下所示。

public delegate void ApplyDelegate();

private void btnApply_Click(object sender, EventArgs e)
{
   btnApply.BeginInvoke(new ApplyDelegate(ApplyAsync));
}

private void ApplyAsync()
{
    bool current = false;
    if (cmbEmergencyLandingMode.SelectedIndex > 0)
    {
        if (m_WantedData != false)
        {
            DialogResult dr = MessageBox.Show(
                this,
                "Are you sure you want to enable Emergency Landing mode?",
                "Warning!",
                MessageBoxButtons.YesNo,
                MessageBoxIcon.Warning);

            //i never get to this point
            current = (dr == DialogResult.Yes);
        }
    }

    if (m_WantedData == current)
    {
        //do something
    }
    else if (m_WantedData != null)
    { 
        //do something else
    }
}

Answer 2

尝试在MessageBox.Show()方法中不指定父表单的情况下显示消息。我不知道为什么但是，当我加载模态窗口时，我遇到了类似的问题。

if (m_WantedData != false)
{
    if (MessageBox.Show("Sample Message", "Are you sure you want to enable Emergency Landing mode?", "Warning!", MessageBoxButtons.YesNo, MessageBoxIcon.Warning) == DialogResult.Yes)
    {
        //DO YOUR STUFF HERE IF YES
    }
    else
    {

    }
}

MessageBox挂起

2 个答案: