这是图书馆管理系统的读者管理，该代码段是为了实现读者的信息修改，在窗口中没有错，可是一运行修改读者信息就出错了，我找了半天也不知道哪错了，谁可以帮我找一下错

[cyjjxn]

if (txtreaderID.Text.Trim() == "")
{
MessageBox.Show("请输入借书证号！", "警告", 0);
return;
}
SqlConnection conn = new SqlConnection(sqlcon);
string sqlstr = "update [TReader] set";
if (txtname.Text.Trim().ToString() != "")
{
sqlstr += "[Name]='" + txtname.Text.Trim() + "',";
}
if (txtspec.Text.Trim() != "")
{
sqlstr += "[Spec]='" + txtspec.Text.Trim() + "',";
}
if (txtborn.Text.Trim() != "")
{
sqlstr += "[Born]='" + txtborn.Text.Trim() + "',";
}
if (txtsex.Text.Trim() != "")
{
sqlstr += "[Sex]='" + txtsex.Text.Trim() + "',";
}
if (txtphoto.Text.Trim() != "")
{
sqlstr += "[Photo]= @Photo";

}
sqlstr += "where ReaderID='" + txtreaderID.Text.Trim() + "'";

SqlCommand cmd = new SqlCommand(sqlstr, conn);
if (txtphoto.Text.Trim() != "")
{
FileStream fs = null;
fs = new FileStream(txtphoto.Text.Trim(), FileMode.Open, FileAccess.Read);
MemoryStream mem = new MemoryStream();
byte[] data1 = new byte[fs.Length];
fs.Read(data1,0,(int)fs.Length);
cmd.Parameters.Add("@Photo", SqlDbType.Image);
cmd.Parameters["@Photo"].Value = data1;
}
try
{
conn.Open();
int yxh = cmd.ExecuteNonQuery();
if (yxh == 1)
{
MessageBox.Show("修改成功！", "提示", 0);
}
else
{
MessageBox.Show("数据库中没有此读者！", "警告", 0);
}
this.tReaderTableAdapter.Fill(this.mBOOKDataSet.TReader);
}
catch (Exception ex)
{
MessageBox.Show("出错，没有完成读者的修改！" + ex.Message, "提示", 0);
}
finally
{
conn.Close();
}

[__天涯寻梦]

假如那些文本框中的信息都有，那
sqlstr += "[Name]='" + txtname.Text.Trim() + "',"; [Name]前面少空格；
sqlstr += "where ReaderID='" + txtreaderID.Text.Trim() + "'"; where 前面少空格，
假如 txtphoto.Text.Trim() != "" 判断不成立，还会多出逗号来。