系统.InvalidOperationException: ExecuteReader: CommandText属性未初
本文关键字：属性 ExecuteReader InvalidOperationException 系统 CommandText | 更新日期: 2023-09-27 18:15:01
当我关闭我的程序，我有这样的错误:系统。InvalidOperationException: ExecuteReader: CommandText属性未初始化有人能帮忙吗?下面是我的代码:
try
{
conn = new SqlConnection();
conn.ConnectionString = @"Data Source=ADMIN-PC'SQLEXPRESS;AttachDbFilename=" +
Environment.CurrentDirectory +
@"'diplom.mdf;Integrated Security=True; User Instance = true";
conn.Open();
SqlCommand myCommand = conn.CreateCommand();
string myComm = "";
if (comboBox1.SelectedIndex == 0)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Директор'";
if (comboBox1.SelectedIndex == 1)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Коммерческий директор'";
if (comboBox1.SelectedIndex == 2)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Супервайзер'";
if (comboBox1.SelectedIndex == 3)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Мерчендайзер'";
if (comboBox1.SelectedIndex == 4)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Торговый агент'";
if (comboBox1.SelectedIndex == 5)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Аналитик'";
if (comboBox1.SelectedIndex == 6)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Главный бухгалтер'";
if (comboBox1.SelectedIndex == 7)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Бухгалтер'";
if (comboBox1.SelectedIndex == 8)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Начальник отдела'";
if (comboBox1.SelectedIndex == 9)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Оператор'";
if (comboBox1.SelectedIndex == 10)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Кассир'";
if (comboBox1.SelectedIndex == 11)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Системный администратор'";
if (comboBox1.SelectedIndex == 12)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Заведующий складом'";
if (comboBox1.SelectedIndex == 13)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Кладовщик'";
if (comboBox1.SelectedIndex == 14)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Грузчик'";
if (comboBox1.SelectedIndex == 15)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Водитель'";
if (comboBox1.SelectedIndex == 16)
myComm = @"SELECT fam, name, patronymic, date_birth, adress, phone_number, salary,
position, brand, model, name_of_department FROM View2 where position = 'Экспедитор'";
myCommand.CommandText = myComm;
SqlDataAdapter dataAdapter = new SqlDataAdapter();
dataAdapter.SelectCommand = myCommand;
DataSet ds = new DataSet();
dataAdapter.Fill(ds, "View2");
dataGridView1.DataSource = ds.Tables["View2"].DefaultView;
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
finally
{
conn.Close();
}
您的comboBox1.SelectedIndex不在0-16之间，因此留下myComm为空字符串。这就是为什么你会得到一个错误。还可以考虑使用switch和default命令。
在执行命令之前，请进行检查。
if(!string.IsNullOrWhiteSpace(myComm))
{
myCommand.CommandText = myComm;
SqlDataAdapter dataAdapter = new SqlDataAdapter();
dataAdapter.SelectCommand = myCommand;
DataSet ds = new DataSet();
dataAdapter.Fill(ds, "View2");
dataGridView1.DataSource = ds.Tables["View2"].DefaultView;
}
您的组合框的SelectedIndex有问题。有人已经说过，如果SelectedIndex不在0到16之间，则不初始化命令文本。我还想对你的代码进行优化，除了where条件外，查询文本总是相同的，所以你可以写
string query = "SELECT fam, name, patronymic, date_birth, adress, phone_number, salary, " +
"position, brand, model, name_of_department FROM View2 " +
"where position = @condition";
string condition = string.Empty;
switch(combobox1.SelectedIndex)
{
case 0:
condition = "Директор";
break;
case 1:
condition = "Коммерческий директор";
break;
..... and so on
}
if(!string.IsNullOrWhiteSpace(condition))
{
myCommand.CommandText = query;
myCommand.Parameters.AddWithValue("@condition", condition);
SqlDataAdapter dataAdapter = new SqlDataAdapter();
dataAdapter.SelectCommand = myCommand;
DataSet ds = new DataSet();
dataAdapter.Fill(ds, "View2");
dataGridView1.DataSource = ds.Tables["View2"].DefaultView;
}