以線程安全的方式從表單元素中檢索屬性值

Question

如果需要調用，我使用此方法courtesy of casperOne來設置表單元素上的屬性值。

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[] { }); 
} 

這工作：

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

出於顯而易見的原因，這是行不通的：

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

是否有類似SynchronizedInvoke可以返回屬性值的函數？這將需要一個通用的返回類型和鑄像這樣：

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

Answer 1

您可以設置匿名方法裏面的變量值：

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