Razor Pages CheckBox throwing error in Edit Page - asp.net-core

Question

I need some help in inserting checkbox value to mssql database and retrieving the same in edit page.
This is model class
public class RequestForm{
[Key]
public int ID { get; set; }
public string OtherCompetitorsChecked { get; set; }
public string OtherCompetitorName { get; set; }
}
This is my RequestForm.cshtml file
<div class="tr">
<div class="td">
<input id="ChkOthers" style="margin-left:40px;" asp-for="RequestForm.OtherCompetitorsChecked" type="checkbox" value="Others" /> Others
</div>
<div class="td">
<input id="CompetitorsOthersName" title="Please Fill In Other Competitor Name" asp-for="RequestForm.OtherCompetitorName" type="text" class="form-control-slp" required disabled style="width:50%" />
</div>
</div>
When checking im inserting the checkbox value into database thats why i used string datatype in model class.Im able to insert the data to the database,when im fetching the data its showing error like below
InvalidOperationException: Unexpected expression result value 'Others' for asp-for. 'Others' cannot be parsed as a 'System.Boolean'.
is there any way to fix this?

Answer 1

InvalidOperationException: Unexpected expression result value 'Others'
for asp-for. 'Others' cannot be parsed as a 'System.Boolean'.
public string OtherCompetitorsChecked { get; set; }
This issue relates the OtherCompetitorsChecked data type. The Input Tag Helper sets the HTML type attribute based on the .NET type. Form the following list, we can see that, for the Input checkbox, the .Net type should be Bool type.
So, to solve the above issue, change the OtherCompetitorsChecked's data type to the bool type:
public class RequestForm
{
[Key]
public int ID { get; set; }
public bool OtherCompetitorsChecked { get; set; }
public string OtherCompetitorName { get; set; }
}
Then, in the Get or Post method, when you set its value, it should be true or false.
public void OnGet()
{
RequestForm = new RequestForm() {
ID = 1001,
OtherCompetitorName = "AA",
OtherCompetitorsChecked = true
};
}
Besides, in your application, might be you want to display a list of selected items using checkbox, and want to use a string type to store the selected value. If that is the case, you could try to use the html <input type="checkbox" name ="selectedCourses"> element to display the items (without using Tag helper) or use a <select> tag, then, in the Post method, get the selected option's value via the html element's name property.
Code like this (you could change the checkbox value to the model data, model detail information, refer this tutorial):
<input type="checkbox" name="selectedCompetitorName" value="Others" />
the Post method:
public void OnPost(string selectedCompetitorName)
{
if (ModelState.IsValid)
{
var data = RequestForm;
}
}
<input id="CompetitorsOthersName" title="Please Fill In Other Competitor Name" asp-for="RequestForm.OtherCompetitorName" type="text"
class="form-control-slp" required disabled style="width:50%" />
At the end, according to the above code, I assume you want to make the CompetitorsOthersName text box readonly, if that is the case, try to remove the disabled attribute, and add the readonly attribute. Because, if using the disabled attribute, after submitting the form, the submitted model's CompetitorsOthersName property will be null. You can check it.