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How to checkNull values using Execute Scalar

PankaJ D

string strmcat = "select idcategory from categories where categorydesc='" + mcategory + "'";
        SqlCommand com = new SqlCommand(strmcat, conn);
        conn.Open();

         Object o = (Object)com.ExecuteScalar();
        if ( o != DBNull.Value)
        {
            idmcat = (int)com.ExecuteScalar();
        }
        conn.Close();
What wrong with this code.When null values return from db then also control goes in if condition.

3 Replies

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Suthish Nair15y ago
Amit,

ExecuteScalar returns null if no value is returned, and DBNull.Value if a null is returned.

Pankaj,

So try like this..
```
if (o != null)
{ ''' }
```
```
or,
```
```
if (! DBNull.Value.Equals(o)) 
      '''
else
      ''
```
0
Amit Choudhary15y ago
i don't think it'll return null it always return an integer or 0 value. so no need to check for null.

Thanks.
0
Syed Shakeer15y ago
Hi,
You can check the object if it is null or not as follows:

Object o = (Object)com.ExecuteScalar();

        if ( o != Null)
        {

         }
0