cast to value type 'System.Int32' failed because the materialized

I am trying to add increment value in database column and getting error

for that i used this way

if (nameexist.Trim().ToUpper() != model.talukname.Trim().ToUpper())
{
var MaxValue = (from t in context.ppatalukmasters
where t.regioncode == model.regioncode
select (int?)t.talukcode).Max() ?? 0;

model.talukcode = MaxValue + 1;

}

but by using this way i cant get increment value

if i use this way

var MaxValue = (from t in context.ppatalukmasters where t.regioncode == model.regioncode select t.talukcode).Max();
model.talukcode = MaxValue + 1;

then i am getting error

How i solve this issue?

To handle the increment value in the database column and resolve the casting error, you can modify your code as follows:

if (nameexist.Trim().ToUpper() != model.talukname.Trim().ToUpper())
{
    var MaxValue = context.ppatalukmasters
        .Where(t => t.regioncode == model.regioncode)
        .Select(t => (int?)t.talukcode)
        .Max() ?? 0;
                          
    model.talukcode = MaxValue + 1;
}

we are using the LINQ query syntax to retrieve the maximum value of talukcode for a specific regioncode. By using the Select method with (int?), we ensure that the nullable integer type is returned. If there are no records matching the condition, the Max method will return null, which we handle using the null-coalescing operator ?? to assign a default value of 0.

You should be able to successfully increment the value of talukcode in your database column.

It's important to note that the casting error you encountered may have been caused by the presence of null values in the talukcode column. By using the nullable integer type (int?), we can handle these null values and avoid the casting error.

1 Reply

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Jayraj Chhaya2y ago
Accepted answer
To handle the increment value in the database column and resolve the casting error, you can modify your code as follows:
```
if (nameexist.Trim().ToUpper() != model.talukname.Trim().ToUpper())
{
    var MaxValue = context.ppatalukmasters
        .Where(t => t.regioncode == model.regioncode)
        .Select(t => (int?)t.talukcode)
        .Max() ?? 0;
                          
    model.talukcode = MaxValue + 1;
}
```
we are using the LINQ query syntax to retrieve the maximum value of talukcode for a specific regioncode. By using the Select method with (int?), we ensure that the nullable integer type is returned. If there are no records matching the condition, the Max method will return null, which we handle using the null-coalescing operator ?? to assign a default value of 0.

You should be able to successfully increment the value of talukcode in your database column.

It's important to note that the casting error you encountered may have been caused by the presence of null values in the talukcode column. By using the nullable integer type (int?), we can handle these null values and avoid the casting error.