无法将“System.Byte”类型的 object 转换为“System.String”类型。

Question

I am trying to populate value from Database to Combobox and when I run it I get this error:

Unable to cast object of type 'System.Byte' to type 'System.String'.'

Status is of type tinyint .

public void FillStatus()
{
    try
    {
        using (SqlConnection conn = new SqlConnection(@"Data Source=(LocalDb)\MSSQLLocalDB;Initial Catalog=DesignSaoOsig1;Integrated Security=True"))
        {
            conn.Open();
            string query = "SELECT DISTINCT Status FROM tblZaposleni_AD";
            SqlCommand cmd = new SqlCommand(query, conn);
            using (SqlDataReader saReader = cmd.ExecuteReader())
            {
                while (saReader.Read())
                {
                    string name = saReader.GetString(0);
                    ddlStatus.Items.Add(name);
                }
            }
        }
    }
    catch (Exception)
    {
        throw;
    }
}

Answer 1

I find where the error comes from. Insted of

string name = saReader.GetString(0);

I just replace this line to this one

 string name = saReader.GetByte(0).ToString();

Answer 2

As SQL Server tinyint is converted to byte in .NET, you need to read it as such, then convert to a string:

byte dbValue = saReader.GetByte(0);
string name = dbValue.ToString();
ddlStatus.Items.Add(name);