asp.net中数据复制的错误消息

Question

我已尝试过以下代码，但它会抛出一个唯一的键约束错误。我希望它是一个弹出式消息;见下面的代码。

using (SqlConnection con2 = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
{
    var fromdate = DateTime.Parse(txtfromdate.Text);
    var todate = DateTime.Parse(txttodate.Text);
    var datedif1 = (todate - fromdate).Days;

    var sqlInsert = new SqlCommand("INSERT INTO datelist ([datedif],[batch],[daywk],[semester],[weekbatch],[subject],[facultyname],[facultyid],[WeekMonth])  VALUES  (@datedif,@batch,@daywk,@semester,@weekbatch,@subject,@facultyname,@facultyid,@weekMonth)", con2);
    var sqlParamater = sqlInsert.Parameters.Add("@datedif", SqlDbType.Date);
    var sqlParameter1 = sqlInsert.Parameters.Add("@batch", SqlDbType.NVarChar);
    var sqlParameter2 = sqlInsert.Parameters.Add("@daywk", SqlDbType.NVarChar);
    var sqlParameter3 = sqlInsert.Parameters.Add("@semester", SqlDbType.NVarChar);
    var sqlParameter4 = sqlInsert.Parameters.Add("@weekbatch", SqlDbType.NVarChar);
    var sqlParameter5 = sqlInsert.Parameters.Add("@subject", SqlDbType.NVarChar);
    var sqlParameter6 = sqlInsert.Parameters.Add("@facultyname", SqlDbType.NVarChar);
    var sqlParameter7 = sqlInsert.Parameters.Add("@facultyid", SqlDbType.NVarChar);
    var sqlParameter8 = sqlInsert.Parameters.Add("@WeekMonth", SqlDbType.NVarChar);

    con2.Open();
    try
    { 
        for (var i = 0; i <= datedif1; i++)
        {
            var consecutiveDate = fromdate.AddDays(i);

            sqlParamater.Value = consecutiveDate;
            sqlParameter1.Value = batch1;
            sqlParameter2.Value = dayweek;
            sqlParameter3.Value = semester;
            sqlParameter4.Value = weekbatch;
            sqlParameter5.Value = subject;
            sqlParameter6.Value = faculty;
            sqlParameter7.Value = facultyid;
            sqlParameter8.Value = weekmonth;

            int s = sqlInsert.ExecuteNonQuery();
        }
        con2.Close();
    }
    catch(ConstraintException ex)
    {
        throw new ApplicationException("data are duplicated");
    }
}

以下是错误的屏幕截图，

Answer 1

您正在捕获ConstraintException，但插入的是SqlException，它不是ConstraintException的子类。改变捕获量，你将得到它。