Question

今天当我在visual studio中运行我的急剧项目时，我遇到了这个错误

System.Data.Entity.dll中出现“System.Data.EntityException” 底层提供程序在Open上失败。

在它工作良好的前几天，这是我的代码，它给出了错误。有人请帮帮我。

    private void dataGridView1_CellEnter(object sender, DataGridViewCellEventArgs e)
    {

        dataGridView1.CurrentRow.HeaderCell.Value = dataGridView1.CurrentRow.Index + 1;

            label2.Text = "";
            dbcontext = new BookDatabase.BooksEntities();
            var bookName = Convert.ToString(dataGridView1.CurrentRow.Cells[1].Value);
            var book = from bok in dbcontext.Books
                       where bok.Title == bookName
                       select bok;
            foreach (var bk in book)//Showing problem here, highlighting book
            {
                dataGridView1.CurrentRow.Cells[0].Value = bk.Code;
                dataGridView1.CurrentRow.Cells[2].Value = bk.Edition;
                var auto = from autho in bk.Authors
                          select autho;
               foreach (var author in auto)
                    dataGridView1.CurrentRow.Cells[3].Value = author.FirstName + " " + author.LastName;

                dataGridView1.CurrentRow.Cells[4].Value = bk.Price;
           }
        }

Answer 1

它是否提供内部异常？它通常更具体。验证数据库服务器是否在线，以及连接字符串是否正确。

System.Data.EntityException发生在System.Data.Entity.dll中

1 个答案: