LINQ XML從另一個表單獲取組合框值＃

Question

我想在兩個窗體之間的標籤中顯示xml信息，但我得到「未將對象引用設置爲對象實例」。我一直在尋找幾個小時，但沒有解決方案。

cbFrom和cbTo是我的兩個textboxs，我需要從一個FORM1發送他們的價值觀到另一個FORM2

public partial class FORM1 : Form 
{ 
    public string combofrom 
    { 
     get { return cbFrom.Text; } 
     set { cbFrom.Text = value; } 
    } 

    public string comboto 
    { 
     get { return cbTo.Text; } 
     set { cbTo.Text = value; } 
    } 
    } 

FORM2提前

public partial class FORM2 : Form 
{ 
public FORM2() 
    { 
     InitializeComponent(); 
    } 

    private FORM1 = new FORM1(); 

    public FORM1(FORM2 form) 
    { 
     this.form = form; 
    } 

    private void button1_Click(object sender, EventArgs e) 
    { 
     XDocument xmlDoc = XDocument.Load("schedulemanager.xml"); 

     var n = from ep in xmlDoc.Descendants("Aircraft") 
       where ep.Attribute("mdy").Equals(form.combofrom.ToString()) 
       select ep; 

     label8.Text = n.FirstOrDefault().ToString();// ****Object reference  
             //not set to an instance of an object 

    } 

謝謝！

UPDATE 最後我找到了一個解決方案。

FORM1

 public void FORM1(object sender, EventArgs e) 
    { 
    FORM2 f2 = new FORM2(this); 
    } 
    /**You don't need any getter or setter 

FORM2

 private FORM2 f2; 
    public frmScheduleResult(frmReservation f) 
    { 
     InitializeComponent(); 
     f2 = f; 

    } 

    var name = xmlDoc.Descendants("Aircraft") 

     .Where(n => n.Attribute("Source").Value == f1.cbFrom.Text) 
     .Select(n => (string)n) 
     .FirstOrDefault();  
     label7.Text = name; 

Answer 1

試試這個：

if(form.combofrom!=null) 
{ 

    var n = (from ep in xmlDoc.Descendants("Aircraft") 
        where ep.Attribute("mdy").Equals(form.combofrom.ToString()) 
        select ep).FirstOrDefault(); 

    if(n!=null) 
    { 
    label8.Text = n.FirstOrDefault().ToString(); 
    } 
} 

Answer 2

試試這個，我希望這將有助於您：

String name = xmlDoc.Descendants("Aircraft") 
       .Elements("Name") 
       .Where(n => (string)n.Attribute("mdy") == form.combofrom.ToString()) 
       .Select(n => (string)n) // get element's value 
       .FirstOrDefault();  // select only first value, if any 

label8.Text = name.ToString();