modelstate.valid n! Model state.valid

Question

Hello, I want to learn basic mvc model from experience developer. what is difference between model state.is valid n !modelstate.is valid? I always confused this topic N give me Both example

Salman Beg · Answer

Hi. If(ModelState.IsValid) means it will check for all the model properties are valid or not with the data.If it returns true then rest of your code execute. If(!ModelState.IsValid) means it will check for the false condition and if some properties are not satisfy with the valid data then also it proceeds. Thanks.

Sreekanth Reddy · Answer

Hi Sonal, Firstly if(true) --> result is true if(!true) --> reuslt is false if(false) --> result is false if(!false) --> result is true. Note : Negotion of true is false & Negotion of false is true. In more simple : !true is false !false is true. Now lets discuss your issue ModelState : modelstate --> means it verifies the validations of the model, based on our data annotations applied / or user provided values in model fields in views. Let us think that we are having form fields as X,Y,Z. Lets apply data annotaion for X , Y & Z. Now think that user didnt provided value for field "Z" and gave values for "X" & "Y". As per the rule we had applied annotations for all 3 fields. But user gave only 2 fields. So we dont want to process forward. Instead we expect to show an error message to the user. So, At this point the "ModelState.Isvalid" becomes failed because user gave 2 values only out of 3 in the model. Now, for the above scenario let us make the valid/not valid by ModelState.IsValid like below : if(ModelState.Isvalid) --> Becomes "false". if(!ModelState.Isvalid) --> Becomes "True" If it helps you, Mark as answer. Thank you.