Question

当我想从访问中检索日期时，我在 cmd1.ExecuteReader 处收到异常错误“没有给出一个或多个参数的值”。这是我的代码

void checking_fields()
    {

        OleDbCommand cmd = new OleDbCommand("select movie_id from event", oc);
        OleDbDataReader ol = cmd.ExecuteReader();
        OleDbCommand cmd1 = new OleDbCommand("select [open date],[close date] from event", oc);
        OleDbDataReader ol1 = cmd1.ExecuteReader();
        while (ol1.Read())
        {
            if (ol1.GetValue(0).ToString() == dateTimePicker1.Value.ToString("MM/dd/yyyy") || 
                ol1.GetValue(1).ToString() == dateTimePicker2.Value.ToString("MM/dd/yyyy"))
                goto abc;
        }
        ol.Read();

        if (textBox1.Text.Equals(ol.GetString(0)))
            label8.Text = "ID already exists";
        else
        {
            insert_database();
            clear();
            this.Close();
        }
        abc:  label8.Text = "Open date or Close date already assigned";
        }

这些是开放日期和结束日期的属性

必需的：无，索引：是（没有重复）， ime_mode：no_control， text_align：中心 show_date_picker：for_dates

因为我是c＃的新手，请帮帮我

Answer 1

您的查询中没有任何参数这意味着您的一个或多个字段名称 Open Date或Close Date
在您的表事件中不存在

Answer 2

似乎您尚未打开连接：

void checking_fields()
{

    OleDbCommand cmd = new OleDbCommand("select movie_id from event", oc);
oc.open();

    OleDbDataReader ol1 = cmd1.ExecuteReader();
    while (ol1.Read())
    {
        if (ol1.GetValue(0).ToString() == dateTimePicker1.Value.ToString("MM/dd/yyyy") || 
            ol1.GetValue(1).ToString() == dateTimePicker2.Value.ToString("MM/dd/yyyy"))
            goto abc;
    }
oc.close();

    OleDbCommand cmd1 = new OleDbCommand("select [open date],[close date] from event", oc);
    oc.open();
    OleDbDataReader ol = cmd.ExecuteReader();
    ol.Read(); // consider revising that section

    if (textBox1.Text.Equals(ol.GetString(0)))
        label8.Text = "ID already exists";
    else
    {
        insert_database();
        clear();
        this.Close();
    }
    abc:  label8.Text = "Open date or Close date already assigned";
    }

我做了一些修改，我执行了一个读者，关闭它，然后执行第二个。

使用c＃“没有给出一个或多个参数的值”

2 个答案: