我们如何处理 gridview/datalist 中下拉列表的 onselectedindexchanged 事件？

Question

I have a simple datalist with a dropdownlist and a textbox.

When the dropdownlist selected index changes, I want to load a value into the textbox in that listbox item (ie, the textbox on that particular row).

<ItemTemplate>
    <asp:DropDownList runat="server" 
        ID="ddlCategory" AutoPostBack="true"
        DataTextField="category"
        DataValueField="category_code" 
        OnSelectedIndexChanged="ddlCategory_SelectedIndexChanged" />                      
    <br />
    Code<asp:TextBox 
        runat="server" 
        ID="txtOutputCode" 
        Text='<%# Bind("output_code") %>' />
</ItemTemplate>

How do I do this?

The challenge I'm facing is how to find the corresponding textbox to update.

Eg for a button I'd pass a commandname, and command arguments. And then I'd handle the event in the gridview or datalist to find the corresponding textbox and update the text. What can we do in case of a selectedindex change of a dropdownlist?

Answer 1

I guess this should work. Try this...

protected void ddlCategory_SelectedIndexChanged(object sender, EventArgs e)
{
   var ddlList= (DropDownList)sender;
   var row = (GridViewRow)ddlList.NamingContainer;
   //get the Id of the row
   var Id = Convert.ToInt32(((Label)row.FindControl("IdColumn")).Text);
}

Answer 2

What you should do is the following:

private SomeObject o = new SomeObject();

private void o_SomeEvent(...) {
}

public TheConstructor() {
    this.o.SomeEvent += new SomeHandler(o_SomeEvent);
}

which means you have to create a new dropdownlist and attach its event to the dropdownlist you have in the gridview on itemdatabound

Answer 3

protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
    {
        DropDownList ddlcouse = (DropDownList)sender;
        DataListItem Grow = (DataListItem)ddlcouse.NamingContainer;
        foreach (DataListItem dst in dstAllSite.Items)
        {
            DropDownList ddl_AccountInfo = (DropDownList)dst.FindControl("ddlAccountInfo");
            if (ddlcouse.SelectedIndex > 0)
            {
                BindAccountDDL(ddl_AccountInfo, ddlcouse.SelectedValue.Trim());
                ddlcouse.Focus();
            }
        }
    }

    private void BindAccountDDL(DropDownList ddlAccountInfo, string ddlcouse)
    {
        csPL.ddlcouse = ddlcouse;
        DataTable dt = csBL.BindAccountInfoDDL(csPL);
        if (dt.Rows.Count > 0)
        {
            ddlAccountInfo.DataSource = dt;
            ddlAccountInfo.DataTextField = "BankName";
            ddlAccountInfo.DataValueField = "BankId";
            ddlAccountInfo.DataBind();
            ddlAccountInfo.Items.Insert(0, "Select");
        }
    }