dynamic query showing 'Unclosed quotation mark after the character string '), - asp.net

Question

i have a stored procedure in which i am getting error 'Unclosed quotation mark after the character string ' having a hard time with the script. please help me to find out what is wrong in my code.
here is my code.
ALTER PROCEDURE [dbo].[usp_Transfer]
#orgid bigint,
#SearchString nvarchar (500) = null,
#LocationId bigint = 0,
#ownerid bigint,
#OrderList varchar(MAX)
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.\
SET NOCOUNT ON;
DECLARE #SQL varchar(MAX)
BEGIN
SET #SQL = 'SELECT ProductID = ii.ProductId,
InvItemId = convert(bigint,0),Name = p.Name,
PrimaryImageID = p.PrimaryImageID,ProductNumberLabel = p.ProductNumberLabel,ProductNumber = p.ProductNumber,
category = isnull(c.Name,''),
qty = ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0.00),
SalePrice= ISNULL(p.SalePrice, 0.00),
EnteredQuantity=(case when (ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0.00) > 1) then 1.00 else ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0.00) end)
,Discount=0,u.UnitName,
u.UnitID
FROM dbo.[Inven] ii
Left Join dbo.[Product] p on ii.ProductId = p.ProductId and p.activestatus=1
Left Join dbo.[category] c on p.DefaultCategoryId = c.CategoryId
Left Join dbo.[Unit] u on p.UnitId=u.UnitId and u.Activestatus=1
WHERE p.OrganizationID = #orgid
AND ii.InventoryID IN(1634)
AND ii.ActiveStatus = 1
AND p.ActiveStatus = 1
AND p.IsDisabled = 0
And p.CanSale = 1
AND ii.InventoryID IN (' + #OrderList + ')
group by ii.ProductId, p.Name, p.PrimaryImageID, p.ProductNumberLabel, p.ProductNumber, c.Name,p.SalePrice,u.unitname,u.UnitID
having ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0) > 0
Order by p.ProductNumber, p.Name, c.Name '
--EXEC(#SQL)
PRINT(#SQL)
END
END

Answer 1

Two things of note.
First, does #OrderList contain any quotes?
Second, this line:
...' WHERE p.OrganizationID = #orgid '
Should be:
....'WHERE p.OrganizationID = ' + #orgid + '...'
The easy way to test if either of these are the cause of the problem is to comment both out, run it and see if it works, if it does then comment them in one at a time to see which one gives you the error.
Finally, you could rewrite this query and avoid using a dynamic query at all. I guess looking at the query you have done it because of the IN (' + #OrderList + ') clause. These posts might help you rework that section:
Parameterize an SQL IN clause
SQL Server - In clause with a declared variable

Answer 2

Update your SP as below:
Note: there are so many errors if solve one like quotation mark, declare variable #orgid and then conversion error
Your initial error due to : category = isnull(c.Name,''), replace it with category = isnull(c.Name,'''')
alter PROCEDURE [dbo].[usp_Transfer]
#orgid bigint=1,
#SearchString nvarchar (500) = null,
#LocationId bigint = 0,
#ownerid bigint=1,
#OrderList varchar(MAX)='1'
AS
BEGIN
-- SET NOCOUNT ON added to prevent extra result sets from
-- interfering with SELECT statements.\
SET NOCOUNT ON;
DECLARE #SQL varchar(MAX)
BEGIN
SET #SQL = 'SELECT ProductID = ii.ProductId,
InvItemId = convert(bigint,0),Name = p.Name,
PrimaryImageID = p.PrimaryImageID,ProductNumberLabel = p.ProductNumberLabel,ProductNumber = p.ProductNumber,
category = isnull(c.Name,''''),
qty = ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0.00),
SalePrice= ISNULL(p.SalePrice, 0.00),
EnteredQuantity=(case when (ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0.00) > 1) then 1.00 else ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0.00) end)
,Discount=0,u.UnitName,
u.UnitID
FROM dbo.[Inven] ii
Left Join dbo.[Product] p on ii.ProductId = p.ProductId and p.activestatus=1
Left Join dbo.[category] c on p.DefaultCategoryId = c.CategoryId
Left Join dbo.[Unit] u on p.UnitId=u.UnitId and u.Activestatus=1
WHERE p.OrganizationID = '+CAST(#orgid AS VARCHAR(10))+'
AND ii.InventoryID IN(1634)
AND ii.ActiveStatus = 1
AND p.ActiveStatus = 1
AND p.IsDisabled = 0
And p.CanSale = 1
AND ii.InventoryID IN (' + #OrderList + ')
group by ii.ProductId, p.Name, p.PrimaryImageID, p.ProductNumberLabel, p.ProductNumber, c.Name,p.SalePrice,u.unitname,u.UnitID
having ISNULL((SUM(ii.[QuantityOnHand]) - SUM(ii.[QuantitySold])), 0) > 0
Order by p.ProductNumber, p.Name, c.Name '
EXEC(#SQL)
PRINT(#SQL)
END
END