[英]got the exception Object reference not set to an instance of an object
我已經開發了一個Windows應用程序(C#.net)。我得到了例外,對象引用未設置為對象的實例。
堆棧跟蹤為
在OnamVideoCable.Bill_Generate.btnBill_Click(Object sender,EventArgs e)中的C:\\ FinalOnam \\ CableOperatorSoftware \\ OnamVideoCable \\ OnamVideoCable \\ Bill Generate.cs:line 179
在System.Windows.Forms.Control.OnClick(EventArgs e)
在System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent)
在System.Windows.Forms.Control.WmMouseUp上(消息和m,MouseButtons按鈕,Int32單擊)
在System.Windows.Forms.Control.WndProc(Message&m)
在System.Windows.Forms.ButtonBase.WndProc(Message&m)
在System.Windows.Forms.Button.WndProc(Message&m)
在System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message&m)
在System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd,Int32 msg,IntPtr wparam,IntPtr lparam)
在System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG&msg)
在System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(Int32 dwComponentID,Int32原因,Int32 pvLoopData)
在System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32原因,ApplicationContext上下文)
在System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32原因,ApplicationContext上下文)
在C:\\ FinalOnam \\ CableOperatorSoftware \\ OnamVideoCable \\ OnamVideoCable \\ Program.cs:的OnamVideoCable.Program.Main()
在System.AppDomain._nExecuteAssembly(程序集程序集,String []參數)
在Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
在System.Threading.ExecutionContext.Run(ExecutionContext執行上下文,ContextCallback回調,對象狀態)
在System.Threading.ThreadHelper.ThreadStart()
碼:
私人void btnBill_Click(object sender,EventArgs e){int CustNo = 0; int PayMonth; objB.OB = Convert.ToDouble(txtOB.Text);
if (ddCustSelect.Text == "All Customers")
{
try
{
DataTable dtCustNo = objCust.GetCustInfoForBill();
foreach (DataRow drCustNo in dtCustNo.Rows)
{
CustNo = Convert.ToInt32(drCustNo["CustNo"]);
DataTable dtR = new DataTable();
dtR=objR.GetLastReceiptInfo(CustNo);
if (dtR != null)
{
if (dtR.Rows.Count > 0)
{
DataRow drR = dtR.Rows[0];
//groupBox1.Visible = true;
//lblReceipt.Text = Convert.ToString(drR["RNo"]);
//lblPaidAmt.Text = Convert.ToString(drR["Amount"]);
// lbloutstand.Text = Convert.ToString(drR["Balance"]);
//lblMonthRate.Text = Convert.ToString(drR["MonthlyRate"]);
DateTime paydate = Convert.ToDateTime(drR["date"]);
//lblPayMonth.Text = Convert.ToString(drR["paydate"]);
PayMonth = paydate.Month;
objB.LastOut = Convert.ToDouble(drR["Balance"]);
total = calculate_bill(PayMonth, ddMonth.SelectedIndex + 1, Convert.ToDouble(drR["Balance"]), Convert.ToDouble(drR["MonthlyRate"]));
}
else
{
PayMonth = ddMonth.SelectedIndex + 1;
DataTable dtRate = objRate.GetExistCustRate(CustNo);
DataRow drRate = dtRate.Rows[0];
//total = calculate_bill(PayMonth, ddMonth.SelectedIndex + 1, 0, Convert.ToDouble(drRate["Total"]));
//objB.LastOut = 0;
total = Convert.ToDouble(drRate["Total"]);
objB.LastOut = total;
}
}
else
{
PayMonth = ddMonth.SelectedIndex + 1;
DataTable dtRate = objRate.GetExistCustRate(CustNo);
DataRow drRate = dtRate.Rows[0];
//total = calculate_bill(PayMonth, ddMonth.SelectedIndex + 1, 0, Convert.ToDouble(drRate["Total"]));
//objB.LastOut = 0;
total = Convert.ToDouble(drRate["Total"]);
objB.LastOut = total;
//MessageBox.Show("Table is null");
}
objB.CustNo = Convert.ToInt32(CustNo);
objB.Month = ddMonth.Text;
objB.Year = ddYear.Text;
objB.Total = total;
DataTable dtBill = new DataTable();
dtBill = objB.checkBill();
if (dtBill != null)
{
if (dtBill.Rows.Count > 0)
{
// MessageBox.Show("Bill is Already Generated");
continue;
}
else
{
objB.GenerateBill();
}
}
else
{
//MessageBox.Show("2nd table is null");
objB.GenerateBill();
}
}
MessageBox.Show("Bill is generated");
}
catch (Exception ex)
{
// MessageBox.Show(ex.Message + CustNo);
throw ex;
}
}
if (ddCustSelect.Text == "Single Customer")
{
try
{
//panelSingle.Visible = true;
// groupBox1.Visible = true;
objB.CustNo = Convert.ToInt32(ddCustNo.Text);
objB.Month = ddMonth.Text;
objB.Year = ddYear.Text;
objB.Total = Convert.ToDouble(lblTotalBill.Text);
if (lbloutstand.Visible)
{
objB.LastOut = Convert.ToDouble(lbloutstand.Text);
}
else
{
objB.LastOut = objB.Total;
}
DataTable dtBill = objB.checkBill();
if (dtBill != null)
{
if (dtBill.Rows.Count > 0)
{
MessageBox.Show("Bill is Already Generated");
}
else
{
if (objB.GenerateBill())
{
MessageBox.Show("Bill is generated..");
}
else
{
MessageBox.Show("Error while generating bill");
}
}
}
else
{
MessageBox.Show("2nd table null");
}
}
catch(Exception)
{
}
}
}----this is line no 179
因此,請仔細查看(或接近-數字可能會少一些)第179行
在OnamVideoCable.Bill_Generate.btnBill_Click(Object sender,EventArgs e)中的C:\\ FinalOnam \\ CableOperatorSoftware \\ OnamVideoCable \\ OnamVideoCable \\ Bill Generate.cs:line 179
那里的東西為空。 添加一個斷點並使用調試器。 請檢查是否為空,或者修復使它意外為空的所有內容。 我無法告訴您什么-我看不到您的代碼!
查看Generate.cs:line 179,檢查您在此行中使用的變量,其中之一為null
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