在asp中單擊「編輯」時會創建重複列：GridView

Question

我有asp:GridView，我使用AutoGenerateEditButton="True"屬性編輯網格行。現在的問題是，每當我點擊Edit按鈕，列再次填充。例如，如果有4列，如果我點擊Edit比相同的4列將重新出現。

.ASPX代碼：

<asp:GridView ID="grdEmpDetail" runat="server" CellPadding="4" ForeColor="#333333" GridLines="None" 
      OnRowEditing="grdEmpDetail_RowEditing" 
      OnRowCancelingEdit="grdEmpDetail_RowCancelingEdit" 
      OnRowUpdated="grdEmpDetail_RowUpdated" 
      AutoGenerateEditButton="True"> 
</asp:GridView> 

代碼背後：要在網格動態綁定數據

protected void Page_Load(object sender, EventArgs e) 
{ 
    WorkSampleBusiness.BusinessObject objBL = new WorkSampleBusiness.BusinessObject(); 
    this.grdEmpDetail.AutoGenerateColumns = false; 
    try 
    { 
     DataTable dt = new DataTable(); 
     dt = objBL.OrderDetail(); 
     foreach (var col in dt.Columns) 
     { 
      if (col.ToString() == "ID" || col.ToString() == "First Name" || col.ToString() == "Last Name" || col.ToString() == "Business Phone" || col.ToString() == "Job Title") 
      { 
       BoundField objBoundField = new BoundField(); 
       objBoundField.DataField = col.ToString(); 
       objBoundField.HeaderText = col.ToString(); 
       this.grdEmpDetail.Columns.Add(objBoundField); 
      } 
     } 
     this.grdEmpDetail.DataSource = dt; 
     this.grdEmpDetail.DataBind(); 
    } 
    catch 
    { 
     throw; 
    } 
} 

手柄編輯模式：

protected void grdEmpDetail_RowEditing(object sender, GridViewEditEventArgs e) 
    { 
     this.grdEmpDetail.EditIndex = e.NewEditIndex; 
     this.grdEmpDetail.DataBind(); 
    } 

protected void grdEmpDetail_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e) 
    { 
     this.grdEmpDetail.EditIndex = -1; 
     this.grdEmpDetail.DataBind(); 
    } 

OUTPUT：這是細

問題：這是我得到問題的地方。

缺少什麼我在這裏？

Answer 1

您未檢查數據綁定代碼中的IsPostBack。因此，每次發佈到代碼被一次又一次執行的頁面時。所以每次你會添加更多的列。

修改您的處理程序，如下所示：

protected void Page_Load(object sender, EventArgs e) 
{ 
    if(!IsPostBack) { 
     // All of your existing code goes here 
    } 
} 

編輯

它比這更復雜一點。當您點擊編輯時，您實際上需要將DataGrid重新綁定到數據源，但您只是不想再次添加列。這就要求你分解一些代碼，這樣就可以重新使用數據綁定的代碼，而不會受到列添加的限制。

首先，讓我們創建一個特定的方法，用於添加出現在輸入DataTable列：

private void AddColumnsToDataGrid(DataTable dt) { 

    foreach (var col in dt.Columns) { 
     if (col.ToString() == "ID" 
      || col.ToString() == "First Name" 
      || col.ToString() == "Last Name" 
      || col.ToString() == "Business Phone" 
      || col.ToString() == "Job Title") 
     { 
      BoundField objBoundField = new BoundField(); 
      objBoundField.DataField = col.ToString(); 
      objBoundField.HeaderText = col.ToString(); 
      this.grdEmpDetail.Columns.Add(objBoundField); 
     } 
    } 

} 

下創建了一種數據綁定一個DataTable到您的網格：

private void DataBindGrid(DataTable dt) { 

    this.grdEmpDetail.DataSource = dt; 
    this.grdEmpDetail.DataBind(); 

} 

現在你已經提取了部分代碼，可以在適當情況下重新使用這些方法，並且只添加一列：

網頁加載處理

protected void Page_Load(object sender, EventArgs e) 
{ 
    if(!IsPostBack) { 

     WorkSampleBusiness.BusinessObject objBL = new WorkSampleBusiness.BusinessObject(); 
     this.grdEmpDetail.AutoGenerateColumns = false; 

     try { 
      DataTable dt = objBL.OrderDetail(); 
      AddColumnsToDataGrid(dt); 
      DataBindGrid(dt); 
     } catch { 
      // Side Note: If you're just re-throwing the exception 
      // then the try/catch block is completely useless. 
      throw; 
     } 

    } 

} 

編輯處理程序

protected void grdEmpDetail_RowEditing(object sender, GridViewEditEventArgs e) 
{ 

    this.grdEmpDetail.EditIndex = e.NewEditIndex; 

    WorkSampleBusiness.BusinessObject objBL = new WorkSampleBusiness.BusinessObject();  
    DataBindGrid(objBL.OrderDetail()); 

} 

protected void grdEmpDetail_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e) 
{ 
    this.grdEmpDetail.EditIndex = -1; 

    WorkSampleBusiness.BusinessObject objBL = new WorkSampleBusiness.BusinessObject();  
    DataBindGrid(objBL.OrderDetail()); 

} 

Answer 2

嘗試：

protected void Page_Load(object sender, EventArgs e) 
{ 
    if (!IsPostBack) 
    { 
     Fill_Grid(); 
    } 
} 
protected Void Fill_Grid() 
{ 

    if (grdEmpDetail.Columns.Count > 0) 
    { 
     for (int n = 0; n < grdEmpDetail.Columns.Count; n++) 
     { 
      grdEmpDetail.Columns.RemoveAt(n); 

     } 
    grdEmpDetail.DataBind(); 
    } 
    this.grdEmpDetail.AutoGenerateColumns = false; 
    WorkSampleBusiness.BusinessObject objBL = new WorkSampleBusiness.BusinessObject(); 
    try 
    { 
     DataTable dt = new DataTable(); 
     dt = objBL.OrderDetail(); 
     foreach (var col in dt.Columns) 
     { 
      if (col.ToString() == "ID" || col.ToString() == "First Name" || col.ToString() == "Last Name" || col.ToString() == "Business Phone" || col.ToString() == "Job Title") 
      { 
       BoundField objBoundField = new BoundField(); 
       objBoundField.DataField = col.ToString(); 
       objBoundField.HeaderText = col.ToString(); 
       this.grdEmpDetail.Columns.Add(objBoundField); 
      } 
     } 
     this.grdEmpDetail.DataSource = dt; 
     this.grdEmpDetail.DataBind(); 
    } 
    catch (exception e1) 
    { 
    } 
} 
protected void grdEmpDetail_RowEditing(object sender, GridViewEditEventArgs e) 
{ 
    this.grdEmpDetail.EditIndex = e.NewEditIndex; 
    Fill_Grid(); 
} 

protected void grdEmpDetail_RowCancelingEdit(object sender, GridViewCancelEditEventArgs e) 
{ 
    this.grdEmpDetail.EditIndex = -1; 
    Fill_Grid(); 
}