Question

我正在尝试更新MS Access中的表，但更新操作不起作用，我没有收到错误。

rowsAffected为0，因此没有更新。

这是我的代码：

public bool UpdateAddress(AddressModel address)
    {
        using (OleDbCommand dbCommand = new OleDbCommand())
        {
            // Set the command object properties
            dbCommand.Connection = new OleDbConnection(this.ConnectionString);
            dbCommand.CommandType = CommandType.Text;
            dbCommand.CommandText = "Update Addresses " +
        " Set [Street] = @Street, [PostalCode] = @PostalCode, " +
        "  [City] = @City, [Contact] = @Contact"+
        " Where [Address_ID] = @Address_ID";

            // Add the input parameters to the parameter collection
            dbCommand.Parameters.AddWithValue("@Street", address.Street);
            dbCommand.Parameters.AddWithValue("@PostalCode", address.PostalCode);
            dbCommand.Parameters.AddWithValue("@City", address.City);
            dbCommand.Parameters.AddWithValue("@Address_ID", address.Address_ID);
            dbCommand.Parameters.AddWithValue("@Contact", address.Contact);

            // Open the connection, execute the query and close the connection
            dbCommand.Connection.Open();
            var rowsAffected = dbCommand.ExecuteNonQuery();
            dbCommand.Connection.Close();

            return rowsAffected > 0;
        }
    }
 AddressModel-Class:
  public class AddressModel
{
    public Int64 Address_ID { get; set; }

    public Int64 Customer_ID { get; set; }

    public string Street { get; set; }

    public string PostalCode { get; set; }

    public string City { get; set; }

    public string Contact { get; set; }

    public bool FirstAddress { get; set; }
}

可能是什么问题？

Answer 1

使用System.Data.OleDb时，参数严格位置。 OleDb忽略参数 names ，只关注参数占位符在CommandText中出现的顺序。因此，您需要.Add或.AddWithValue参数的顺序与它们在CommandText中显示的顺序完全相同。

在您的情况下，您需要颠倒最后两个dbCommand.Parameters.AddWithValue语句的顺序：@Address_ID必须是添加的最后一个参数，因为它的占位符在CommandText中最后出现。

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