我正在为 GetSourceAttachment
方法下载 word 文件。当此方法返回空字节时,我的字节 Attachment
数组会出错:
Object reference not set instance of object
当我在 if
条件下检查 Attachment
的长度时出现错误。
谁能帮我默认初始化字节数组,然后检查长度?
try
{
byte[] Attachment = null ;
string Extension = string.Empty;
ClsPortalManager objPortalManager = new ClsPortalManager();
Attachment = objPortalManager.GetSourceAttachment(Convert.ToInt32(hdnSourceId.Value), out Extension);
if (Attachment.Length > 0 && Attachment != null)
{
DownloadAttachment("Attacment", Attachment, Extension);
}
else
{
ClientScript.RegisterStartupScript(typeof(Page), "SymbolError", "<script type='text/javascript'>alert('Attachment is not Uploaded !');</script>");
}
}
catch
{
}
最佳答案
就这样
if (Attachment != null && Attachment.Length > 0)
来自 && Operator
The conditional-AND operator (&&) performs a logical-AND of its bool operands, but only evaluates its second operand if necessary.
关于c# - 如何检查字节数组是否为空?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/16476267/