如何检查已经在C＃中的文件夹，文件上传或图像 [英] How to check already file upload or image in folder in c#

问题描述

我已经创建使用asp.net和c＃学生的详细信息。

I have been created student details using asp.net and c#.

我最近添加的像场，当我编辑的详细信息，并编辑某些字段没有提交（编辑如有必要）图像，submit..It显示请上传您的形象的警告。

I added image field recently, when i edit the details, and edit some of the fields without image filed(edit if necessary), and submit..It shows "please upload your image" in alert.

所以，我需要检查，如果图像是images文件夹为空，并在文件上传

So i need to check if image is empty in images folder and also in file upload.

下面是我的code：

code-背后：

protected void btnsub_Click(object sender, EventArgs e)
        {
            SqlConnection con = Connection.DBconnection();
            if (Textid.Text.Trim().Length > 0)
            {
                SqlCommand com = new SqlCommand("StoredProcedure3", con);
                com.CommandType = CommandType.StoredProcedure;
                com.Parameters.AddWithValue("@id", Textid.Text.Trim());
                com.Parameters.AddWithValue("@Name", Textusername.Text.Trim());
                com.Parameters.AddWithValue("@Class", Textclass.Text.Trim());
                com.Parameters.AddWithValue("@Section", Textsection.Text.Trim());
                com.Parameters.AddWithValue("@Address", Textaddress.Text.Trim());
                try
                {
                    string filename = string.Empty;
                    if (fileupload.PostedFile.FileName.Length > 0)
                    {
                        filename = Path.GetFileName(fileupload.PostedFile.FileName);
                        fileupload.SaveAs(Server.MapPath("~/Images/" + filename));
                    }
                    com.Parameters.AddWithValue("@Image",(filename.Length>0)? "Images/" + filename:string.Empty);
                    com.ExecuteNonQuery();                    
                }
                catch (Exception ex)
                {
                    btnsub.Text = ex.Message;
                }
                Response.Redirect("studententry.aspx");
            }
            else
            {
                SqlCommand com = new SqlCommand("StoredProcedure1", con);
                com.CommandType = CommandType.StoredProcedure;
                com.Parameters.AddWithValue("@Name", Textusername.Text.Trim());
                com.Parameters.AddWithValue("@Class", Textclass.Text.Trim());
                com.Parameters.AddWithValue("@Section", Textsection.Text.Trim());
                com.Parameters.AddWithValue("@Address", Textaddress.Text.Trim());
                try
                {
                    string filename = string.Empty;
                    if (fileupload.PostedFile.FileName.Length > 1)
                    {
                        filename = Path.GetFileName(fileupload.PostedFile.FileName);
                        fileupload.SaveAs(Server.MapPath("~/Images/" + filename));
                    }
                    com.Parameters.AddWithValue("@Image",(filename.Length>0)? "Images/" + filename:string.Empty);
                    com.ExecuteNonQuery();                    
                }
                catch (Exception ex)
                {
                    btnsub.Text = ex.Message;
                }
                Response.Redirect("studententry.aspx");
            }
        }
        protected void btnrst_Click(object sender, EventArgs e)
        {
            Textid.Text = string.Empty;
            Textusername.Text = string.Empty;
            Textclass.Text = string.Empty;
            Textsection.Text = string.Empty;
            Textaddress.Text = string.Empty;
        }
        protected void GridView1_RowCommand(object sender, GridViewCommandEventArgs e)
        {
            SqlConnection con = Connection.DBconnection();

            if (e.CommandName == "EditRow")
            {

                GridViewRow gr = (GridViewRow)((Button)e.CommandSource).NamingContainer;
                int index = gr.RowIndex; 
                hiddenfield.Value = index.ToString(); 
                Textid.Text = gr.Cells[0].Text;
                Textusername.Text = gr.Cells[1].Text;
                Textclass.Text = gr.Cells[2].Text;
                Textsection.Text = gr.Cells[3].Text;
                Textaddress.Text = gr.Cells[4].Text;
                Image1.ImageUrl = ((System.Web.UI.WebControls.Image)gr.Cells[5].Controls[0]).ImageUrl;               
            }
            else if (e.CommandName == "Deleterow")
            {
                SqlCommand com = new SqlCommand("StoredProcedure4", con);
                com.CommandType = CommandType.StoredProcedure;
                com.Parameters.AddWithValue("@ID", Convert.ToInt32(e.CommandArgument));
                var id = Int32.Parse(e.CommandArgument.ToString());                
                com.ExecuteNonQuery();
                Response.Redirect("studententry.aspx");
            }
        }
        protected void GridView1_SelectedIndexChanged(Object sender, EventArgs e)
        {
            int index = GridView1.SelectedIndex;
            hiddenfield.Value = index.ToString();
        }

ASPX：

<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="server">

    <center><div><h4>Student Registration</h4></div></center>
<div class="tblalign">
    <table style="width: 100%;">
    <tr>
    <td><asp:HiddenField ID="hiddenfield" runat="server" /> 
    <asp:TextBox ID="Textid" runat="server" Visible="false"></asp:TextBox>
    </td>

    </tr>
        <tr>
            <td>
                <asp:Label ID="Label1" runat="server" Text="Name"></asp:Label>

            </td>
            <td>
                &nbsp;
            </td>
            <td>
                <asp:TextBox ID="Textusername" runat="server"></asp:TextBox>

            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label2" runat="server" Text="Class"></asp:Label>

            </td>
            <td>
                &nbsp;
            </td>
            <td>
                <asp:TextBox ID="Textclass" runat="server"></asp:TextBox>

            </td>
        </tr>
        <tr>
            <td>
                <asp:Label ID="Label3" runat="server" Text="Section"></asp:Label>

            </td>
            <td>
                &nbsp;
            </td>
            <td>
                <asp:TextBox ID="Textsection" runat="server"></asp:TextBox>
            </td>
        </tr>
        <tr>
        <td>
            <asp:Label ID="Label5" runat="server" Text="Address"></asp:Label>
        </td>

        <td>
            &nbsp;
        </td>
        <td>
            <asp:TextBox ID="Textaddress" runat="server"></asp:TextBox>
        </td>
        </tr>
        <tr>
            <td>
            <asp:Label ID="Label4" runat="server" Text="Image"></asp:Label>
            </td>
            <td>
            &nbsp;
        </td>
        <td>
            <asp:Image ID="Image1" runat="server" ControlStyle-Width="50" ControlStyle-Height = "50"  />

        </td>
        <td>
        <asp:FileUpload ID="fileupload" runat="server" />  
         </td>
        </tr>
        <tr>
        <td>
            <asp:Button ID="btnsub" runat="server" Text="Submit" OnClick="btnsub_Click" OnClientClick="return register();" />
            <asp:Button ID="btnrst" runat="server" Text="Reset" OnClick="btnrst_Click" />
        </td>
        <td>
        </td>            
        <td>            
        </td>
    </tr>

</table></div>
<br />
<br />
<center><div><h4>Student Records</h4></div></center><br /> <br />
    <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" 
        DataKeyNames="ID" DataSourceID="SqlDataSource1" 
        OnRowCommand="GridView1_RowCommand" 
        EnablePersistedSelection="True" BackColor="White" 
        OnSelectedIndexChanged="GridView1_SelectedIndexChanged">
        <Columns>
            <asp:BoundField DataField="ID" HeaderText="ID" InsertVisible="False" 
                ReadOnly="True" SortExpression="ID" />
            <asp:BoundField DataField="Name" HeaderText="Name" SortExpression="Name" />
            <asp:BoundField DataField="Class" HeaderText="Class" SortExpression="Class" />
            <asp:BoundField DataField="Section" HeaderText="Section" 
                SortExpression="Section" />
            <asp:BoundField DataField="Address" HeaderText="Address" 
                SortExpression="Address" />
                <asp:ImageField DataImageUrlField="Image" HeaderText="Image" ControlStyle-Width="50" ControlStyle-Height = "50">                
                </asp:ImageField> 
            <asp:TemplateField HeaderText="Edit">
               <ItemTemplate>
                 <asp:Button runat="server" ID="btnedit" Text="Edit" CommandName="EditRow"></asp:Button>                    
               </ItemTemplate>
                <ControlStyle BorderColor="#CCFF66" />
          </asp:TemplateField>
          <asp:TemplateField HeaderText="Delete">
          <ItemTemplate>
                 <asp:Button runat="server" ID="btndelete" Text="Delete" CommandArgument='<%# Eval("Id") %>' CommandName="Deleterow"></asp:Button>                    
               </ItemTemplate>
          </asp:TemplateField>            
        </Columns>
        <SelectedRowStyle BackColor="#FF66FF" />
    </asp:GridView>
        <asp:SqlDataSource ID="SqlDataSource1" runat="server" 
        ConnectionString="<%$ ConnectionStrings:ConnectionString %>" 
        SelectCommand="StoredProcedure2"          
        SelectCommandType="StoredProcedure">
            <DeleteParameters>
                <asp:Parameter Name="ID" />
                <asp:Parameter Name="Name" />
                <asp:Parameter Name="Class" />
                <asp:Parameter Name="Section" />
                <asp:Parameter Name="Image" />
            </DeleteParameters>
            <UpdateParameters>
                <asp:Parameter Name="ID" />
                <asp:Parameter Name="Name" />
                <asp:Parameter Name="Class" />
                <asp:Parameter Name="Section" />
                <asp:Parameter Name="Image" />
            </UpdateParameters>
    </asp:SqlDataSource>
</asp:Content>

输出

我觉得在editrow命令，我需要检查的条件。其实我是新来的.NET。

I think in editrow command, i need to check the condition. Actually i'm new to .net.

因此​​，谁能帮我解决这个问题。

So can anyone help me to fix this problem.

任何帮助将是非常美联社preciated。

Any help would be highly appreciated.

谢谢，

推荐答案

要检查特定的文件使用 File.Exists（路径），这将返回指示一个布尔值在路径中的文件是否存在。

To check for specific files use File.Exists(path), which will return a boolean value indicating whether the file at path exists.

System.IO.File.Exists(path)

随着你code是同步的，它可以检查图像上传到文件夹后的图像是否将被立即装载。例如：

As your code is synchronous, it is possible to check whether the image is loaded immediately after uploading an image to the folder. For example:

try
  {
     string filename = string.Empty;
     if (fileupload.PostedFile.FileName.Length > 0)
        {
           filename = Path.GetFileName(fileupload.PostedFile.FileName);
           fileupload.SaveAs(Server.MapPath("~/Images/" + filename));
        }     
     string imgAddress = Path.GetFileName(fileupload.PostedFile.FileName);   
     //check whether your image is created:
     bool isExist=System.IO.File.Exists(imgAddress);
     com.Parameters.AddWithValue("@Image",(filename.Length>0)? "Images/" + filename:string.Empty);
     com.ExecuteNonQuery();                    
  }
catch (Exception ex)
{
   btnsub.Text = ex.Message;
}

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