捕捉在C#中的异常 [英] Catching an Exception in C#
本文介绍了捕捉在C#中的异常的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有一个简单的按钮添加
I have a simple button ADD
和ADD_Click code是:
And ADD_Click code is:
protected void Add_Click(object sender, EventArgs e)
{
string strConnectionString = ConfigurationManager.ConnectionStrings["SqlServerCstr"].ConnectionString;
SqlConnection myConnection = new SqlConnection(strConnectionString);
myConnection.Open();
string hesap = Label1.Text;
string musteriadi = DropDownList1.SelectedItem.Value;
string avukat = DropDownList2.SelectedItem.Value;
SqlCommand cmd = new SqlCommand("INSERT INTO AVUKAT VALUES (@MUSTERI, @AVUKAT, @HESAP)", myConnection);
cmd.Parameters.AddWithValue("@HESAP", hesap);
cmd.Parameters.AddWithValue("@MUSTERI", musteriadi);
cmd.Parameters.AddWithValue("@AVUKAT", avukat);
cmd.Connection = myConnection;
SqlDataReader dr = cmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
Response.Redirect(Request.Url.ToString());
myConnection.Close();
}
我要的是,如果有人添加具有相同 HESAP
(主键)一个数据我想这个词的警报()函数。 已经有一个相同的数据或任何话。无所谓。
What i want is, if anybody adding a data with same HESAP
(primary key) i want a alert() function with this words. "Already there is a same data" or any words. Doesn't matter.
我怎样才能做到这一点?
How can i do that?
注意:我想一样的HESAP值获取和捕获错误
NOTE: I want just the same HESAP value getting and catching an error.
推荐答案
试试这个:
protected void Add_Click(object sender, EventArgs e)
{
string hesap = Label1.Text;
string musteriadi = DropDownList1.SelectedItem.Value;
string avukat = DropDownList2.SelectedItem.Value;
string strConnectionString = ConfigurationManager.ConnectionStrings["SqlServerCstr"].ConnectionString;
using (SqlConnection myConnection = new SqlConnection(strConnectionString))
{
myConnection.Open();
using (SqlCommand cmd = new SqlCommand("INSERT INTO AVUKAT VALUES (@MUSTERI, @AVUKAT, @HESAP)", myConnection))
{
cmd.Parameters.AddWithValue("@HESAP", hesap);
cmd.Parameters.AddWithValue("@MUSTERI", musteriadi);
cmd.Parameters.AddWithValue("@AVUKAT", avukat);
cmd.Connection = myConnection;
try
{
cmd.ExecuteNonQuery();
}
catch (SqlException ex)
{
if (ex.Number == 2627)
{
// Add a javascript alert to let the user know that the same HESAP value already exists.
}
else
{
// Rethrow the exception.
throw;
}
}
}
Response.Redirect(Request.Url.ToString());
myConnection.Close();
}
}
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