diff --git a/HJGL_DS/FineUIPro.Web/WeldMat/Stock/StockInEdit.aspx.cs b/HJGL_DS/FineUIPro.Web/WeldMat/Stock/StockInEdit.aspx.cs
index f0373f5..ad582ea 100644
--- a/HJGL_DS/FineUIPro.Web/WeldMat/Stock/StockInEdit.aspx.cs
+++ b/HJGL_DS/FineUIPro.Web/WeldMat/Stock/StockInEdit.aspx.cs
@@ -403,12 +403,15 @@ namespace FineUIPro.Web.WeldMat.Stock
                     if (weld != null)
                     {
                         Model.Weld_StockIn stockIn = BLL.StockInService.GetStockInById(this.StockInId);
-                        decimal remainingAmount = Funs.GetNewDecimalOrZero(this.txtAmount.Text.Trim()) - (stockIn.UsingAmount ?? 0);
-                        if (weld.ConvertValue > 0)
+                        if (stockIn != null)
                         {
-                            this.lbRemainingAmount.Text = (remainingAmount * weld.ConvertValue.Value).ToString("0.####");
+                            decimal remainingAmount = Funs.GetNewDecimalOrZero(this.txtAmount.Text.Trim()) - (stockIn.UsingAmount ?? 0);
+                            if (weld.ConvertValue > 0)
+                            {
+                                this.lbRemainingAmount.Text = (remainingAmount * weld.ConvertValue.Value).ToString("0.####");
+                            }
+                            this.lbReAmount.Text = remainingAmount.ToString("0.####");
                         }
-                        this.lbReAmount.Text = remainingAmount.ToString("0.####");
                         //if (weld.ConvertValue.HasValue)
                         //{
                         //    decimal? amountCov = Funs.GetNewDecimal(this.txtWeight.Text.Trim()) / weld.ConvertValue;