C# 在gridview edititemtemplate 内绑定下拉列表

Binding dropdownlist inside gridview edititemtemplate

提问by Prashanth

I'm not able to bind my dropdownlist present in edititem template . I am getting null reference when i try to access it.

我无法绑定我的下拉列表存在于 edititem 模板中。当我尝试访问它时，我得到了空引用。

My design:

我的设计：

<asp:TemplateField HeaderText ="Category">
    <ItemTemplate >
    <asp:Label ID="drpcategory" Text ='<%#Bind("category") %>' runat ="server" />
    </ItemTemplate>
    <EditItemTemplate>
        <asp:DropDownList ID="drpcategory1"  AppendDataBoundItems="True" runat="server" >
        </asp:DropDownList>
    </EditItemTemplate>
</asp:TemplateField> 

My code behind:

我背后的代码：

protected void gv_RowEditing(object sender, GridViewEditEventArgs e)
{
    gv_table1.EditIndex = e.NewEditIndex;
    DropDownList drpcategory1 = ((DropDownList)gv_table1.Rows[e.NewEditIndex].Cells[8].FindControl("drpcategory1"));
    //BindDropDown(drpcategory1);
    dt = con.GetData("Select category_name from category");

    String str = gv_table1.Rows[e.NewEditIndex].FindControl("drpcategory1").GetType().ToString();
    //((DropDownList)gv_table1.Rows[e.NewEditIndex].Cells[8].FindControl("drpcategory1")).DataSource = dt;
    drpcategory1.DataSource = dt;
    drpcategory1.DataTextField = "category_name";
    drpcategory1.DataValueField = "category_name";
    drpcategory1.DataBind();

    this.setgrid();
}

I've tried looking on the net and tried many things in vain. I am new to asp. Thanks in advance. I would like the dropdown to be bound only when user enters edit mode.

我试过在网上看，但尝试了很多东西都徒劳无功。我是asp的新手。提前致谢。我希望仅在用户进入编辑模式时绑定下拉列表。

采纳答案by Satinder singh

Code Behind:Tested Code and also set dropdown-list selected value on edit mode

代码隐藏：测试代码并在编辑模式下设置下拉列表选择值

protected void gv_RowDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        if ((e.Row.RowState & DataControlRowState.Edit) > 0)
        {
            DropDownList ddList= (DropDownList)e.Row.FindControl("drpcategory1");
            //bind dropdown-list
            DataTable dt = con.GetData("Select category_name from category");
            ddList.DataSource = dt;
            ddList.DataTextField = "category_name";
            ddList.DataValueField = "category_name";
            ddList.DataBind();

            DataRowView dr = e.Row.DataItem as DataRowView;
            //ddList.SelectedItem.Text = dr["category_name"].ToString();
            ddList.SelectedValue = dr["category_name"].ToString();
        }
    }
}

protected void gv_RowEditing(object sender, GridViewEditEventArgs e)
{
    gv.EditIndex = e.NewEditIndex;
    gridviewBind();// your gridview binding function
}

Detailed Blog Article : How to bind drop-down list inside gridview edit template

详细博客文章：如何在gridview编辑模板中绑定下拉列表

回答by nunespascal

The event RowEditingoccurs just before a row is edited.

该事件RowEditing发生在编辑行之前。

You should use the RowDataBoundevent instead.

您应该改用该RowDataBound事件。

protected void gv_RowDataBound(object sender, GridViewRowEventArgs e)
{
   if (gv.EditIndex == e.Row.RowIndex && 
       e.Row.RowType==DataControlRowType.DataRow) 
   {       
       DropDownList drpcategory1 = (DropDownList)e.Row.FindControl("drpcategory1"); 
       //bind the control
   }
}

回答by Mohmedsadiq

You have to use RowDataBound event to bind the dropdown control for edited row. Please use below method in RowDataBound event.

您必须使用 RowDataBound 事件来绑定编辑行的下拉控件。请在 RowDataBound 事件中使用以下方法。

        protected void gv_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowState == DataControlRowState.Edit)
        {
            DropDownList drpcategory1 = (DropDownList)e.Row.FindControl("drpcategory1");
            DataTable dt = con.GetData("Select category_name from category");
            drpcategory1.DataSource = dt;
            drpcategory1.DataTextField = "category_name";
            drpcategory1.DataValueField = "category_name";
            drpcategory1.DataBind();
        }
    }

Hope this will help you.

回答by R.Priya

protected void gvProject_RowDataBound(object sender, GridViewRowEventArgs e)
    {
        try
        {
            string Active = "";
            if (e.Row.DataItem != null)
            { 
                if ((e.Row.RowState & DataControlRowState.Edit) > 0)
                {
                    Label lblEditActive = (Label)e.Row.FindControl("lblUP_ET_ActiveStatus");
                    if (lblEditActive.Text != string.Empty)
                    {
                        Active = lblEditActive.Text.Trim();
                    }

                    DropDownList ddlActive = (DropDownList)e.Row.FindControl("ddlUP_ET_ActiveStatus");
                    ddlActive.Items.Clear();
                    ddlActive.Items.Add("True");
                    ddlActive.Items.Add("False"); 
                    ddlActive.DataBind(); 
                    ddlActive.Items.FindByText(Active).Selected = true;
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }       

回答by Linh Dao

I do it like this. In which, Name and Id are two fields of Company object:

我这样做。其中，Name和Id是Company对象的两个字段：

HTML Code:

HTML代码：

<asp:TemplateField HeaderText="C?ng ty">
    <EditItemTemplate>
        <asp:DropDownList ID="ddlCompanyEdit" DataSource="<%# PopulateddlCompanyEdit() %>" DataValueField="Id" DataTextField="Name" runat="server"></asp:DropDownList>
    </EditItemTemplate>
    <ItemTemplate>
        <asp:Label ID="lbCompany" runat="server" Text='<%#Bind("Company") %>'></asp:Label>
    </ItemTemplate>
</asp:TemplateField>

C# code behind:

后面的 C# 代码：

protected IEnumerable<Company> PopulateddlCompanyEdit()
{
    using (var bkDb = new BrickKilnDb())
    {
        return bkDb.Companies.ToList();
    }
}