GridView에 빈 행 추가

Question

작은 문제 나는 수정할 수없는 코드가 있습니다. 새로운 빈 행을 추가해야하는 ImageButton이있는 GridView가 있습니다. 어떤 이유로이 오류를 얻을 :

Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] CTI_DFC.Default.gv_Steps_RowCommand(Object sender, GridViewCommandEventArgs e) +469
System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +172
System.Web.UI.WebControls.GridViewRow.OnBubbleEvent(Object source, EventArgs e) +163 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +83
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3771

그래서이 인의 GridView 내가 가진 :

<asp:GridView ID="gv_Steps" runat="server" CssClass="lbl_user" Font-Names="Verdana" Font-Size="10px" HeaderStyle-Height="23.5px" HorizontalAlign="Center" 
    RowStyle-Height="23.5px" ShowHeaderWhenEmpty="True" style="z-index: 1; left: 8px; top: 143px; position: absolute; height: 20px; width: 1178px;" AutoGenerateColumns="False" OnRowCommand="gv_Steps_RowCommand"> 
    <AlternatingRowStyle BackColor="#DCE4FF" /> 
    <Columns> 
     <asp:TemplateField HeaderText="Step" HeaderStyle-HorizontalAlign="Left" > 
      <ItemTemplate> 
       <asp:TextBox ID="txt_Step" HeaderStyle-HorizontalAlign="Left" runat="server" Width="150px" Text='<%# Bind("Step") %>'/> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField HeaderText="Server" HeaderStyle-HorizontalAlign="Left" > 
      <ItemTemplate> 
       <asp:TextBox ID="txt_Server" HeaderStyle-HorizontalAlign="Left" runat="server" Width="150px" Text='<%# Bind("Server") %>'/> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField HeaderText="Type" HeaderStyle-HorizontalAlign="Left" > 
      <ItemTemplate> 
       <asp:TextBox ID="txt_Type" HeaderStyle-HorizontalAlign="Left" runat="server" Width="150px" Text='<%# Bind("Type") %>'/> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField HeaderText="Job" HeaderStyle-HorizontalAlign="Left" > 
      <ItemTemplate> 
       <asp:TextBox ID="txt_Job" HeaderStyle-HorizontalAlign="Left" runat="server" Width="150px" Text='<%# Bind("Job") %>'/> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField HeaderText="Number" HeaderStyle-HorizontalAlign="Left" > 
      <ItemTemplate> 
       <asp:TextBox ID="txt_Number" HeaderStyle-HorizontalAlign="Left" runat="server" Width="150px" Text='<%# Bind("Number") %>'/> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField HeaderText="" ItemStyle-Width="15px" ItemStyle-Wrap="false"> 
      <ItemTemplate> 
       <asp:ImageButton ID="btn_AddRow" runat="server" AlternateText="Add Row" CommandArgument="<%# Container.DataItemIndex %>" CommandName="Add" ImageUrl="./Img/ADD.png" ToolTip="Add Row without Change" /> 
      </ItemTemplate> 
     </asp:TemplateField> 
     <asp:TemplateField HeaderText="" ItemStyle-Width="15px" ItemStyle-Wrap="false"> 
      <ItemTemplate> 
       <asp:ImageButton ID="btn_DeleteRow" runat="server" AlternateText="Delete Row" CommandArgument="<%# Container.DataItemIndex %>" CommandName="Delete" ImageUrl="./Img/DEL.png" ToolTip="Delete Row without Change" /> 
      </ItemTemplate> 
     </asp:TemplateField> 
    </Columns> 
    <HeaderStyle BackColor="#0B4DA2" Font-Bold="True" ForeColor="White" /> 
    <RowStyle Height="23px" /> 
</asp:GridView> 

을 그리고 이것은 내가 할 노력하고있어 어떻게 C# 코드입니다 :

protected void gv_Steps_RowCommand(object sender, GridViewCommandEventArgs e) 
{ 
    int intIndex = Convert.ToInt32(e.CommandArgument); //will be used for Delete 

    if (e.CommandName == "Delete" && (gv_Steps.Rows.Count > 1)) 
    { 
     //Nothing done yet 
    } 
    if (e.CommandName == "Add") 
    { 
     DataTable dt = gv_Steps.DataSource as DataTable; 
     DataRow dr = dt.NewRow(); 
     dt.Rows.Add(dr); 

     gv_Steps.DataSource = dt; 
     gv_Steps.DataBind(); 
    } 
} 

조언 해 주셔서 감사합니다!

편집

내 DataTable을가 비어 있고 그런 식으로 작동하지 않습니다 지금은 이해하지만 어떻게 다시 새로운 빈 행과의 GridView는 DataSet에 얻을 수 있습니까? 나는 같은 오류와 같이 그것을 시도 :

protected void gv_Steps_RowCommand(object sender, GridViewCommandEventArgs e) 
    { 
     int intIndex = Convert.ToInt32(e.CommandArgument); //will be used for Delete 

     if (e.CommandName == "Delete" && (gv_Steps.Rows.Count > 1)) 
     { 
      //Nothing done yet 
     } 
     if (e.CommandName == "Add") 
     { 
      DataTable dt = GridviewToDataTable(); 
      DataRow dr = dt.NewRow(); 
      dt.Rows.Add(dr); 

      gv_Steps.DataSource = dt; 
      gv_Steps.DataBind(); 
     } 
    } 

private DataTable GridviewToDataTable() 
    { 
     DataTable dt = new DataTable(); 
     dt.Columns.Add(new DataColumn("Step", typeof(string))); 
     dt.Columns.Add(new DataColumn("Server", typeof(string))); 
     dt.Columns.Add(new DataColumn("Type", typeof(string))); 
     dt.Columns.Add(new DataColumn("Job", typeof(string))); 
     dt.Columns.Add(new DataColumn("Number", typeof(string))); 

     foreach (GridViewRow row in gv_Steps.Rows) 
     { 
      dt.Rows.Add(); 
      dt.Rows[row.RowIndex][0] = ((TextBox)row.FindControl("Step")).Text; 
      dt.Rows[row.RowIndex][1] = ((TextBox)row.FindControl("Server")).Text; 
      dt.Rows[row.RowIndex][2] = ((TextBox)row.FindControl("Type")).Text; 
      dt.Rows[row.RowIndex][3] = ((TextBox)row.FindControl("Job")).Text; 
      dt.Rows[row.RowIndex][4] = ((TextBox)row.FindControl("Number")).Text; 
     } 

     return dt; 
    } 

오류 내가 얻을 :

Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] CTI_DFC.Default.GridviewToDataTable() +1161
CTI_DFC.Default.gv_Steps_RowCommand(Object sender, GridViewCommandEventArgs e) +392
System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +172
System.Web.UI.WebControls.GridViewRow.OnBubbleEvent(Object source, EventArgs e) +163 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +83
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3771

편집 2

은 다음과 같이 그것을 시도 : 내가 얻을

protected void gv_Steps_RowCommand(object sender, GridViewCommandEventArgs e) 
    { 
     int intIndex = Convert.ToInt32(e.CommandArgument); //will be used for Delete 

     if (e.CommandName == "Delete" && (gv_Steps.Rows.Count > 1)) 
     { 
      //Nothing done yet 
     } 
     if (e.CommandName == "Add") 
     { 
      DataTable dt = GridviewToDataTable(gv_Steps); 
      DataRow dr = dt.NewRow(); 
      dt.Rows.Add(dr); 

      gv_Steps.DataSource = dt; 
      gv_Steps.DataBind(); 
      GridviewToDataTable(gv_Steps); 
     } 
    } 
private DataTable GridviewToDataTable(GridView gv) 
    { 
     DataTable dt = new DataTable(); 
     dt.Columns.Add(new DataColumn("Step", typeof(string))); 
     dt.Columns.Add(new DataColumn("Server", typeof(string))); 
     dt.Columns.Add(new DataColumn("Type", typeof(string))); 
     dt.Columns.Add(new DataColumn("Job", typeof(string))); 
     dt.Columns.Add(new DataColumn("Number", typeof(string))); 
     foreach (GridViewRow row in gv.Rows) 
     { 
      dt.Rows.Add(); 
      dt.Rows[row.RowIndex][0] = ((TextBox)row.FindControl("Step")).Text; 
      dt.Rows[row.RowIndex][1] = ((TextBox)row.FindControl("Server")).Text; 
      dt.Rows[row.RowIndex][2] = ((TextBox)row.FindControl("Type")).Text; 
      dt.Rows[row.RowIndex][3] = ((TextBox)row.FindControl("Job")).Text; 
      dt.Rows[row.RowIndex][4] = ((TextBox)row.FindControl("Number")).Text; 
     } 
     gv.DataSource = dt; 
     gv.DataBind(); 
     return dt; 
    } 

오류 :

Object reference not set to an instance of an object. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[NullReferenceException: Object reference not set to an instance of an object.] CTI_DFC.Default.GridviewToDataTable(GridView gv) +1145
CTI_DFC.Default.gv_Steps_RowCommand(Object sender, GridViewCommandEventArgs e) +407
System.Web.UI.WebControls.GridView.HandleEvent(EventArgs e, Boolean causesValidation, String validationGroup) +172
System.Web.UI.WebControls.GridViewRow.OnBubbleEvent(Object source, EventArgs e) +163 System.Web.UI.Control.RaiseBubbleEvent(Object source, EventArgs args) +83
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3771

기타 조언이 있으십니까?

솔루션

내가 그것을했다, 그것은 다음과 같이 수행되었다 :

private DataTable GridviewToDataTable(GridView gv) 
    { 
     DataTable dt = new DataTable(); 
     dt.Columns.Add(new DataColumn("Step", typeof(string))); 
     dt.Columns.Add(new DataColumn("Server", typeof(string))); 
     dt.Columns.Add(new DataColumn("Type", typeof(string))); 
     dt.Columns.Add(new DataColumn("Job", typeof(string))); 
     dt.Columns.Add(new DataColumn("Number", typeof(string))); 
     foreach (GridViewRow row in gv.Rows) 
     { 
      dt.Rows.Add(); 
      dt.Rows[row.RowIndex][0] = (row.FindControl("txt_Step") as TextBox).Text; 
      dt.Rows[row.RowIndex][1] = (row.FindControl("txt_Server") as TextBox).Text; 
      dt.Rows[row.RowIndex][2] = (row.FindControl("txt_Type") as TextBox).Text; 
      dt.Rows[row.RowIndex][3] = (row.FindControl("txt_Job") as TextBox).Text; 
      dt.Rows[row.RowIndex][4] = (row.FindControl("txt_Number") as TextBox).Text; 
     } 
     lbl_Fehlermeldung.Text = dt.Rows[0][0].ToString(); 
     lbl_Fehlermeldung.Visible = true; 
     gv.DataSource = dt; 
     gv.DataBind(); 
     return dt; 
    } 

Answer 1

귀하의 데이터 소스가 하늘이 당신의 DataTable은 객체를 null로 변환되고, 예외가 throwed 이유

Answer 2

코드가 비어있는 경우 gridview에만 적합합니다. 행 색인을 증가시키지 않으므로.

gridview에 새 행을 추가 할 때 약간의 문제가 있습니다.

에 이전에 datasource이 있습니까? datasource이 이미있는 경우 datasource을 viewstate에 저장하고 새 행을 추가하기 전에 gridview에 이전 데이터를 추출한 다음 새 행을 추가해야합니다.코드 아래

는

팔로우

viewstate

private void SetInitialRow() 
{ 
    DataTable dt = new DataTable(); 
    DataRow dr = null; 
    dt.Columns.Add(new DataColumn("RowNumber", typeof(string))); 
    dt.Columns.Add(new DataColumn("Column1", typeof(string))); 
    dt.Columns.Add(new DataColumn("Column2", typeof(string))); 
    dt.Columns.Add(new DataColumn("Column3", typeof(string))); 
    dr = dt.NewRow(); 
    dr["RowNumber"] = 1; 
    dr["Column1"] = string.Empty; 
    dr["Column2"] = string.Empty; 
    dr["Column3"] = string.Empty; 
    dt.Rows.Add(dr); 
    //dr = dt.NewRow(); 

    //Store the DataTable in ViewState 
    ViewState["CurrentTable"] = dt; 

    Gridview1.DataSource = dt; 
    Gridview1.DataBind(); 
} 

에서 datasource 저장 먼저 설정 초기 행 page_load

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (!Page.IsPostBack) 
    { 
     SetInitialRow(); 
    } 
} 

에서 설정 *** *** ***에 새 행을 추가 gridview

private void AddNewRowToGrid() 
{ 
    int rowIndex = 0; 

    if (ViewState["CurrentTable"] != null) 
    { 
     DataTable dtCurrentTable = (DataTable)ViewState["CurrentTable"]; 
     DataRow drCurrentRow = null; 
     if (dtCurrentTable.Rows.Count > 0) 
     { 
      for (int i = 1; i <= dtCurrentTable.Rows.Count; i++) 
      { 
       //extract the TextBox values 
       TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1"); 
       TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2"); 
       TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3"); 

       drCurrentRow = dtCurrentTable.NewRow(); 
       drCurrentRow["RowNumber"] = i + 1; 

       dtCurrentTable.Rows[i - 1]["Column1"] = box1.Text; 
       dtCurrentTable.Rows[i - 1]["Column2"] = box2.Text; 
       dtCurrentTable.Rows[i - 1]["Column3"] = box3.Text; 

       rowIndex++; 
      } 
      dtCurrentTable.Rows.Add(drCurrentRow); 
      ViewState["CurrentTable"] = dtCurrentTable; 

      Gridview1.DataSource = dtCurrentTable; 
      Gridview1.DataBind(); 
     } 
    } 
    else 
    { 
     Response.Write("ViewState is null"); 
    } 

    //Set Previous Data on Postbacks 
    SetPreviousData(); 
} 

*** 설정 이전 데이터

private void SetPreviousData() 
{ 
    int rowIndex = 0; 
    if (ViewState["CurrentTable"] != null) 
    { 
     DataTable dt = (DataTable)ViewState["CurrentTable"]; 
     if (dt.Rows.Count > 0) 
     { 
      for (int i = 0; i < dt.Rows.Count; i++) 
      { 
       TextBox box1 = (TextBox)Gridview1.Rows[rowIndex].Cells[1].FindControl("TextBox1"); 
       TextBox box2 = (TextBox)Gridview1.Rows[rowIndex].Cells[2].FindControl("TextBox2"); 
       TextBox box3 = (TextBox)Gridview1.Rows[rowIndex].Cells[3].FindControl("TextBox3"); 

       box1.Text = dt.Rows[i]["Column1"].ToString(); 
       box2.Text = dt.Rows[i]["Column2"].ToString(); 
       box3.Text = dt.Rows[i]["Column3"].ToString(); 

       rowIndex++; 
      } 
     } 
    } 
} 

*** 버튼을 호출 클릭

protected void ButtonAdd_Click(object sender, EventArgs e) 
    { 
     AddNewRowToGrid(); 
    } 

SORCE 링크 https://www.aspsnippets.com/Articles/Add-new-Row-to-GridView-on-Button-Click-in-ASPNet.aspx