What is the difference between TempData keep() and peek() function?

Once TempData is read the current reques it's not available in the subsequents request.if we want TempData to be read and also avalaible in the subsequents request then after reading we need to call keep method. the more shortcut way to achieving the same is by using peek this function helps to read as well advices MVC to maintain TampData for the subsequents request.

http://www.c-sharpcorner.com/UploadFile/ansh06031982/using-tempdata-peek-and-keep-in-Asp-Net-mvc/

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TempData Keep() & Peek(): Most of the preliminary developers know the basic thing about this is: "TempData is used to preserve the data for next request".... i.e. Once the data is read by the view its lost, and not available for next request...... This is true but its half truth. The oth

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Cool... The query is so simple. Why to make its answer complex. Lemme try to explain in simple words. TempData Keep() & Peek(): Most of the preliminary developers know the basic thing about this is: "TempData is used to preserve the data for next request".... i.e. Once the data is read by the view its lost, and not available for next request...... This is true but its half truth. The other half is: The data can be retained & preserved for next request, and here comes Keep() & Peek() Both Keep() & Peek() is used to tell the server to keep this data for next request even if its read by view. This was the basic knowledge. You can read further if wanna know in detail. In detail: There are mainly 4 conditions when data is/can be preserved: 1. Is the data NOT read by view 2. Is the data READ by view 3. data read and its marked as Keep() 4. data marked as Peek() and then its read The above 4 conditions are quite clear. 1. Is the data NOT read by view: Data will be available for next request if its not read. 2. Is the data READ by view: Data will not be available for next request if its read by view. 3. data read and its marked as Keep(): data will be available for next request if its marked as Keep() after reading the data. 4. data marked as Peek() and then its read: Data will be available for next request if ts marked as Peek() and then read. Note: something we noted here is that, Keep is used after reading the data where as Peek() is used before reading data. e.g.: @TempData["userName "]; <---- read the data TempData.Keep("userName "); <--- marked with Keep() --------- var userName = TempData.Peek("userName ").ToString(); Thanks & Enjoy :-)

temdata uses TempDataDictionary where every data read, will be marked as available for deletion, keep() and peek() both are used to retain data, the only difference is, keep() will be used to retain data that has been marked for deletion (Read and Keep), whereas peek() will be used where you want to read data without marking it for deletion.

temdata uses TempDataDictionary where every data read, will be marked as available for deletion, keep() and peek() both are used to retain data, the only difference is, keep() will be used to retain data that has been marked for deletion (Read and Keep), whereas peek() will be used where you want to read data without marking it for deletion.

Most of the MVC developer knows that TempData is used to preserve data for a single request but reality is that TempData can pass data for next request also. In this article we will discuss how to persist data with TempData using Keep and Peek method as well we will also see the difference between Keep and Peek method. Normally MVC developer knows that TempData is used to preserve data for a single request. This request can traverse through multiple actions or controllers until it displays the view on the browser: But the reality is that in the same session (without closing the browser), if a new or second request is initiated then "TempData" may be persisted but it depends on 4 conditions: Not Read Normal Read Read and Keep Peek and Read Let me describe all these conditions in detail: Not Read If you set a TempData in your action method and if you do not read it in your view then TempData will be persisted and will be available in next request. Normal Read If you set a TempData in your action method and if you read it in your view then TempData will not be persisted and will not be available in next request. You may use TempData to display its data directly. @TempData["Message"]; You may fetch TempData in your view and store in a variable. string message = TempData["Message"]; Read and Keep If you set a TempData in your action method and if you read it in your view and call the "Keep" method then TempData will be persisted and will be available in next request. We can save TempData value using keep method after reading value from TempData. There are two overloads for Keep method. void Keep() This method you can use when all items in TempData you want to retain and does not allow deletion for any TempData’s items. @TempData["Message"]; TempData.Keep(); void Keep(string key) This method you can use when particular TempData’s value you want to persist and does not allow deletion for that particular TempData’s value. Rest of the TempData’s values will be deleted. @TempData["Message"]; TempData.Keep("Message"); You can understand it by this way, by calling "Keep" method, you are specifying that keep (persist) this TempData for next request. Peek and Read If you set a TempData in your action method and if you read it in your view by calling "Peek" method then TempData will be persisted and will be available in next request. string message = TempData.Peek("Message").ToString(); Peek method is doing both tasks here in same statement: reading and persisting data. This diagram will describe about all these conditions: Difference between Keep and Peek Method Marking for Deletion When an object in a TempDataDictionary is read, it is marked for deletion but we can use Keep and Peek method to save Data with TempData. Once we retrieved value from object than it is marked for deletion, with Keep method we can later save object from Deletion. It means first deletion marking is happened then saving using Keep method. With Peek method we can retain TempData value without marking for deletion in a single call. It means deletion marking is not happening in case of Peek method. It directly persist TempData. Saving Specific TempData Keep provides 2 overload methods. One can save particular TempData on condition based and second can save all TempData’s value. Peek method always saves particular TempaData’s value

using keep() first read temp date then keep for tempdata for next read. while peek() is used for read and keep simultaneously.

temdata uses TempDataDictionary where every data read, will be marked as available for deletion, keep() and peek() both are used to retain data, the only difference is, keep() will be used to retain data that has been marked for deletion (Read and Keep), whereas peek() will be used where you want to read data without marking it for deletion. Example: @TempData["MyData"]; TempData.Keep("MyData"); here we are reading it first after that unmarking it using keep. stringstr = TempData.Peek("Td").ToString(); here we are reading without marking it for deletion.

You can use Peek when you always want to retain the value for another request. Use Keep when retaining the value depends on additional logic. For more details, Please read below link : https://hassantariqblog.wordpress.com/2016/09/02/mvc-when-to-use-keep-vs-peek-in-asp-net-mvc/

If both are same then why we have two methods ????

If you read the “TempData” and call the “Keep” method, it will be persisted. If you read “TempData” by using the “Peek” method, it will persist for the next request.

keep() and peek() both are used to retain value after reading.Generally after reading value it gets deleted.but if you call them on tempdata it maintain value for another request .