以线程安全的方式从表单元素检索属性值

Question

如果需要调用，我使用此方法courtesy of casperOne在表单元素上设置属性值。

static void SynchronizedInvoke(ISynchronizeInvoke sync, Action action)
{
    // If the invoke is not required, then invoke here and get out.
    if (!sync.InvokeRequired)
    {
        // Execute action.
        action();

        // Get out.
        return;
    }

    // Marshal to the required thread.
    sync.Invoke(action, new object[] { });
}

这有效：

// Set a label's text
SynchronizedInvoke(lblCurrCalStatus, () => lblCurrCalStatus.Text = "Downloading...");

由于显而易见的原因，这不起作用：

// Retrieve a label's text
string calStatus = SynchronizedInvoke(lblCurrCalStatus, () => lblCurrCalStatus.Text);

是否有类似于SynchronizedInvoke的函数可以返回属性值？这需要一个通用的返回类型和类似的转换：

// Retrieve a label's text
string calStatus = (string)SynchronizedInvokeReturn(lblCurrCalStatus, () => lblCurrCalStatus.Text);

Answer 1

您可以在匿名方法中设置变量值：

string calStatus = string.Empty;
SynchronizedInvoke(lblCurrCalStatus, () => calStatus = lblCurrCalStatus.Text);