Question

您好任何人都可以帮助我:)。

这段代码中的问题是什么？

protected void LinkButton1_Click(object sender, EventArgs e)
{
    //object o = new object();
    //Control co = new Control();
    //co = GridView1.FindControl("EmpFileUpload");
    FileUpload f = new FileUpload();
    (System.Web.UI.WebControls.FileUpload)f = (System.Web.UI.WebControls.FileUpload)(GridView1.FindControl("EmpFileUpload"));

    if (f.HasFile)
    {
        SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["schoolsConnectionString"].ConnectionString);
        conn.Open();
        SqlCommand insertCommand = new SqlCommand("insert_Empimg", conn);

        insertCommand.Parameters.Add("Emp_imgPath", SqlDbType.NVarChar, 0).Value =f.FileName;

        insertCommand.CommandType = CommandType.StoredProcedure;
        insertCommand.ExecuteNonQuery();

        conn.Close();
    }



}

Answer 1

首先

FileUpload f = new FileUpload();
(System.Web.UI.WebControls.FileUpload)f = (System.Web.UI.WebControls.FileUpload(GridView1.FindControl("EmpFileUpload"));

如果你在下一行重新分配它，则不需要'新'f。

FileUpload f = (System.Web.UI.WebControls.FileUpload(GridView1.FindControl("EmpFileUpload"));

其次，您需要检查f的声音是否为空。

if(f != null && f.HasFile)

Answer 2

您的FindControl可能无法找到上传控件。

让我们整理一下这段代码..

//You dont need the `new` as you are assigning to the result of `FindControl`
FileUpload f = GridView1.FindControl("EmpFileUpload") as FileUpload;

//Check for null here, this is probably your problem
if (f !=null && f.HasFile)     
{       
    //Using statement takes care of closing our connection and disposing our objects.
    using (SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["schoolsConnectionString"].ConnectionString))
    {
         conn.Open();         
         using (SqlCommand insertCommand = new SqlCommand("insert_Empimg", conn))
         {          
             insertCommand.Parameters.Add("Emp_imgPath", SqlDbType.NVarChar, 0).Value =f.FileName;          
             insertCommand.CommandType = CommandType.StoredProcedure;         
             insertCommand.ExecuteNonQuery();
         }
    }
}

然后我们可以查看为什么找不到它，是否可以粘贴声明EmpFileUpload

的标记

Answer 3

FileUpload f = (System.Web.UI.WebControls.FileUpload)(GridView1.FindControl("EmpFileUpload"));

通过GridView1.FindControl("EmpFileUpload")查找控件取决于您将file upload放在grid view中的位置。请放置aspx镜头以清楚地识别您放置控件的位置。以正确的方式访问它。

你调用的对象是空的

3 个答案: