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Code  ›  [C#] GridView編輯時，自動修改Textbox欄位值 - iT 邦幫忙::一起幫忙解決難題，拯救 IT 人的一天
asp gridview
https://ithelp.ithome.com.tw/questions/10199872
儒雅的皮带
1 年前
TextBox1、TextBox2原本都是有值的 
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
  DateTime dt = DateTime.Now;
  string nowDate = dt.ToString("yyyy-MM-dd");
  string nowTime = dt.ToString("HH:mm:ss");
  TextBox TB1 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox1");
  TextBox TB2 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox2");
  TB1.Text = nowDate; 
  TB2.Text = nowTime; 

但按下編輯時會出現 "並未將物件參考設定為物件的執行個體。"

錯誤點在 TB1.Text = nowDate; 開始


請問這一句錯的點在哪邊?

                    
應該有指定TextBox1和TextBox2的ID給那兩個輸入框吧~?


目前我寫的範例可以取到這兩個輸入框, aspx的宣告如下, 而.cs程式跟你一樣.


<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" OnRowEditing="GridView1_RowEditing">
	 <Columns>
		 <asp:TemplateField HeaderText="Id">
			 <ItemTemplate>
				<asp:TextBox ID="TextBox1" runat="server" Text='<%# Eval("Id") %>'></asp:TextBox>
			</ItemTemplate>
		 </asp:TemplateField>
		 <asp:TemplateField HeaderText="Name">
			<ItemTemplate>
				<asp:TextBox ID="TextBox2" runat="server" Text='<%# Eval("Name") %>'></asp:TextBox>
			</ItemTemplate>
		 </asp:TemplateField>
		 <asp:CommandField ShowEditButton="True" />
	 </Columns>
 </asp:GridView>

2020/08/25 更新


後續大大提供的Code是用EditItemTemplate, 所以在RowUpdating無法直接取到元件, 必須改在RowDataBound使用. 要觸發RowDataBound是要有GridView1.DataBind()被呼叫~


protected void GridView1_RowDataBound(object sender, GridViewRowEventArgs e)
	if (e.Row.RowType == DataControlRowType.DataRow && e.Row.RowState == DataControlRowState.Edit)
		if (e.Row.RowIndex == GridView1.EditIndex)
			 string nowDate = dt.ToString("yyyy-MM-dd");
			 string nowTime = dt.ToString("HH:mm:ss");
			 TextBox TB1 = (TextBox)e.Row.FindControl("TextBox1");
			 TextBox TB2 = (TextBox)e.Row.FindControl("TextBox2");
			 TB1.Text = nowDate; 
			 TB2.Text = nowTime; 
我在同一頁有DetailsView1 << 新增資料用

有一個GridViewRow2 <<查詢料號，選取會帶入基本資料到DetailsView1

DetailsView1上其中兩格，如本問題假設為TextBox1和TextBox2

在Page_Load的時候，會帶入當下的日期、時間到


DetailsView1新增完畢後，GridViewRow2會顯示本日新增的項目

在GridViewRow2樣板內，日期、時間假設也是TextBox1和TextBox2

有確認過GridViewRow2內的日期和時間編號沒錯

所以才有我上述描述語法


下方確實取不到TB1和TB2的值，莫非是e.NewEditIndex 這邊有問題?


TextBox TB1 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox1");
TextBox TB2 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox2");
Response.Write(TB1.ToString());
Response.Write(TB2.ToString());
我在同一頁有DetailsView1 << 新增資料用
有一個GridViewRow2 <<查詢料號，選取會帶入基本資料到DetailsView1
DetailsView1上其中兩格，如本問題假設為TextBox1和TextBox2
在Page_Load的時候，會帶入當下的日期、時間到
DetailsView1新增完畢後，GridViewRow2會顯示本日新增的項目
在GridViewRow2樣板內，日期、時間假設也是TextBox1和TextBox2
有確認過GridViewRow2內的日期和時間編號沒錯
所以才有我上述描述語法
下方確實取不到TB1和TB2的值，莫非是e.NewEditIndex 這邊有問題?
TextBox TB1 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox1");
TextBox TB2 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox2");
Response.Write(TB1.ToString());
Response.Write(TB2.ToString());
                        
                        
時間卻沒真的寫入TextBox1


protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
  DateTime dt = DateTime.Now;
  string nowDT = dt.ToString("yyyy/MM/dd HH:mm:ss");
  TextBox TB1 = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox1");
  TB1.Text = nowDT.ToString();
  Response.Write(TB1.Text);
  //Response.End();

明天我開一個測試頁，只放兩個textbox看看

protected void GridView1_RowUpdating(object sender, GridViewUpdateEventArgs e)
  DateTime dt = DateTime.Now;
  string nowDT = dt.ToString("yyyy/MM/dd HH:mm:ss");
  TextBox TB1 = (TextBox)GridView1.Rows[e.RowIndex].FindControl("TextBox1");
  TB1.Text = nowDT.ToString();
  Response.Write(TB1.Text);
  //Response.End();
明天我開一個測試頁，只放兩個textbox看看
                            
text2.aspx 只放入兩個欄位，一個是pk，一個是編輯時要自動填入DateTime


GridView1


<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="RTR_Num" DataSourceID="SqlDataSource1" OnRowEditing="GridView1_RowEditing">
<Columns>
   <asp:CommandField ShowEditButton="True" />
   <asp:BoundField DataField="RTR_Num" HeaderText="RTR_Num" ReadOnly="True" SortExpression="RTR_Num" />
   <asp:TemplateField HeaderText="Last_Modify" SortExpression="Last_Modify">
       <EditItemTemplate>
          <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Last_Modify") %>'></asp:TextBox>
       </EditItemTemplate>
       <ItemTemplate>
          <asp:Label ID="Label1" runat="server" Text='<%# Bind("Last_Modify") %>'></asp:Label>
       </ItemTemplate>
   </asp:TemplateField>
 </Columns>
</asp:GridView>

SqlDataSource


<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:STOCK_MGMTConnectionString %>" DeleteCommand="DELETE FROM [Recd_Trans_Record] WHERE [RTR_Num] = @RTR_Num" InsertCommand="INSERT INTO [Recd_Trans_Record] ([RTR_Num], [Last_Modify]) VALUES (@RTR_Num, @Last_Modify)" SelectCommand="SELECT [RTR_Num], [Last_Modify] FROM [Recd_Trans_Record]" UpdateCommand="UPDATE [Recd_Trans_Record] SET [Last_Modify] = @Last_Modify WHERE [RTR_Num] = @RTR_Num">
   <DeleteParameters>
      <asp:Parameter Name="RTR_Num" Type="String" />
   </DeleteParameters>
   <InsertParameters>
      <asp:Parameter Name="RTR_Num" Type="String" />
      <asp:Parameter Name="Last_Modify" Type="DateTime" />
   </InsertParameters>
    <UpdateParameters>
      <asp:Parameter Name="Last_Modify" Type="DateTime" />
      <asp:Parameter Name="RTR_Num" Type="String" />
    </UpdateParameters>
</asp:SqlDataSource>

protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
   DateTime dt = DateTime.Now;
   string nowDT = dt.ToString("yyyy/MM/dd HH:mm:ss");
   TextBox TB1 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox1");
   TB1.Text = nowDT.ToString();

為了方便測試，我只開兩個位置

並且不手動調整程式碼跟SQL

按下編輯按鈕時，一樣會報錯

GridView1
<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False" DataKeyNames="RTR_Num" DataSourceID="SqlDataSource1" OnRowEditing="GridView1_RowEditing">
<Columns>
   <asp:CommandField ShowEditButton="True" />
   <asp:BoundField DataField="RTR_Num" HeaderText="RTR_Num" ReadOnly="True" SortExpression="RTR_Num" />
   <asp:TemplateField HeaderText="Last_Modify" SortExpression="Last_Modify">
       <EditItemTemplate>
          <asp:TextBox ID="TextBox1" runat="server" Text='<%# Bind("Last_Modify") %>'></asp:TextBox>
       </EditItemTemplate>
       <ItemTemplate>
          <asp:Label ID="Label1" runat="server" Text='<%# Bind("Last_Modify") %>'></asp:Label>
       </ItemTemplate>
   </asp:TemplateField>
 </Columns>
</asp:GridView>
SqlDataSource
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings:STOCK_MGMTConnectionString %>" DeleteCommand="DELETE FROM [Recd_Trans_Record] WHERE [RTR_Num] = @RTR_Num" InsertCommand="INSERT INTO [Recd_Trans_Record] ([RTR_Num], [Last_Modify]) VALUES (@RTR_Num, @Last_Modify)" SelectCommand="SELECT [RTR_Num], [Last_Modify] FROM [Recd_Trans_Record]" UpdateCommand="UPDATE [Recd_Trans_Record] SET [Last_Modify] = @Last_Modify WHERE [RTR_Num] = @RTR_Num">
   <DeleteParameters>
      <asp:Parameter Name="RTR_Num" Type="String" />
   </DeleteParameters>
   <InsertParameters>
      <asp:Parameter Name="RTR_Num" Type="String" />
      <asp:Parameter Name="Last_Modify" Type="DateTime" />
   </InsertParameters>
    <UpdateParameters>
      <asp:Parameter Name="Last_Modify" Type="DateTime" />
      <asp:Parameter Name="RTR_Num" Type="String" />
    </UpdateParameters>
</asp:SqlDataSource>
protected void GridView1_RowEditing(object sender, GridViewEditEventArgs e)
   DateTime dt = DateTime.Now;
   string nowDT = dt.ToString("yyyy/MM/dd HH:mm:ss");
   TextBox TB1 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox1");
   TB1.Text = nowDT.ToString();
為了方便測試，我只開兩個位置
並且不手動調整程式碼跟SQL
按下編輯按鈕時，一樣會報錯
![https://ithelp.ithome.com.tw/upload/images/20200825/20082456XSVS6MzzBa.jpg](https://ithelp.ithome.com.tw/upload/images/20200825/20082456XSVS6MzzBa.jpg)
                            
如果先試試

TextBox TB1 = new TextBox();

TB1 = (TextBox)GridView1.Rows[e.NewEditIndex].FindControl("TextBox1");

再用TB1去接值呢??

我將語法寫在 GridView1 編輯按鈕 Button1_Click2內


protected void Button1_Click2(object sender, EventArgs e)
   DateTime dt = DateTime.Now;
   string toDate = dt.ToString("yyyy-MM-dd");
   string nowTime = dt.ToString("HH:mm:ss");
   GridViewRow gvw = (GridViewRow)((Button)sender).NamingContainer;
   TextBox TB1 = (TextBox)gvw.FindControl("TextBox1");
   TextBox TB1 = (TextBox)gvw.FindControl("TextBox2");
   TB1.Text = toDate;
   TB2.Text = nowTime;

結果還是不行

   DateTime dt = DateTime.Now;
   string toDate = dt.ToString("yyyy-MM-dd");
   string nowTime = dt.ToString("HH:mm:ss");
   GridViewRow gvw = (GridViewRow)((Button)sender).NamingContainer;
   TextBox TB1 = (TextBox)gvw.FindControl("TextBox1");
   TextBox TB1 = (TextBox)gvw.FindControl("TextBox2");
   TB1.Text = toDate;
   TB2.Text = nowTime;
結果還是不行
 
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