![](/img/trans.png)
[英]Silverlight adding to List<T> throws Object reference not set to an instance of an object
[英]Object reference not set to an instance of an object on adding an object to a list
在以下代碼中,對於我來說還是一個未知的原因,它一直在標題中引發異常。
try
{
conn.Open();
createDraw.ExecuteNonQuery();
rdr = getDrawId.ExecuteReader();
string rd = rdr[0].ToString();
int tid = Int32.Parse(rd);
Drawing dr = new Drawing(tid, pos, orientation, defaultColour, 200.0, 300.0, fname, "local");
this.NoteScatterView.Items.Add(dr.getSvi());
if (dr != null) { drawings.Add(dr); }
}
catch (Exception ex) { Microsoft.Surface.UserNotifications.RequestNotification("Unable to create Drawing", ex.Message + "in Session.createDrawing"); }
我只是想在圖形列表中添加圖形對象
private List<Drawing> drawings;
供以后使用,但我不知道為什么拋出此異常。
確保圖紙已初始化:
private List<Drawing> drawings = new List<Drawing>();
您需要創建一個List實例
private List<Drawing> drawings = new List<Drawing>();
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.