要注意的是：
enctype="multipart/form-data"不可少，enctype默认编码是“application/x-www-form-urlencoded”，设置enctype="multipart/form-data"，用于二进制方式上传文件。
为防止文件名乱码，防止乱七八糟字符URL传递中出现问题，返回文件名到前台时进行HttpUtility.UrlEncode，在前台JS中取文件名时进行decodeURIComponent。
重置文件选择框时，要把文件选择框临时插入到临时表单，通过表单的reset方法重置。
顺便贴上解析上传的csv文件的code
解析csv文件
private DataTable ImportDataTable(string filepath)
{
DataTable mydt = new DataTable("myTableName");
mydt.Columns.Add("Data ID", System.Type.GetType("System.String"));
mydt.Columns.Add("Field Name", System.Type.GetType("System.String"));
mydt.Columns.Add("New Value", System.Type.GetType("System.String"));
DataRow mydr;
using (System.IO.StreamReader mysr = new System.IO.StreamReader(filepath))
{
int data;
char current;
StringBuilder text = new StringBuilder();
IDictionary<int, List<string>> results = new Dictionary<int, List<string>>();
bool isInYinHao = false; ;
int lineId = 1;
int index = 0;
while (true)
{
data = mysr.Read();
if (data != -1)
{
current = (char)data;
if (current == '"')
{
if (isInYinHao)
{
isInYinHao = false;
}
else
{
if (index > 0)
{
text.Append(current);
}
isInYinHao = true;
}
}
else if (current == ',')
{
if (isInYinHao)
{
text.Append(current);
}
else
{
SaveResult(results, lineId, text);
index = 0;
continue;
}
}
else if (current == 'r')
{
if (isInYinHao)
{
text.Append(current);
}
}
else if (current == 'n')
{
if (isInYinHao)
{
text.Append(current);
}
else
{
SaveResult(results, lineId, text);
index = 0;
lineId++;
continue;
}
}
else if (current == ' ')
{
}
else
{
text.Append(current);
}
index++;
}
else
{
//Read to file end.
SaveResult(results, lineId, text);
break;
}
}
foreach (int id in results.Keys)
{
mydr = mydt.NewRow();
for (int i = 0; i < results[id].Count; i++)
{
if (i > 2)
{
break;
}
mydr[i] = results[id][i];
}
mydt.Rows.Add(mydr);
}
}
return mydt;
}
private void SaveResult(IDictionary<int, List<string>> results, int lineId, StringBuilder text)
{
if (!results.ContainsKey(lineId))
{
results.Add(lineId, new List<string>());
}
results[lineId].Add(text.ToString());
text.Remove(0, text.Length);
}
点击下载
