Update textbox via onchange event of a dropdownlist while editing in gridview

Question

Hi All,

I am trying to update a textbox within currently edited row within a gridview on when changing items on a dropdownlist and I cant quite get it going in VB. I found this code in c# but dont know if Im on the right track?

Can you please offer some help?

Thanks for your time.

PS this code is for an onmouseover event but the point is to update the textbox while in edit mode.

'>

Js:

function ChangeValue( i)
{
var t=i.id
document.getElementById(t).value="Hello World!";
}

Answer 1

I think should be like

document.getElementById('<%= TextBoxUnitPrice.ClientID %>').value = "Hello World!";

Answer 2

Try the following:

Put the following script in head tag:

<script language="javascript" type="text/javascript">

    function ChangeValue(ddl,txtid)
    {
        var txt=document.getElementById(txtid);
        var dval= ddl.options[ddl.selectedIndex].value;
        if(dval=="1")
        {
         txt.value="It's 1";
        }
        if(dval=="2")
        {
         txt.value="It's 2";
        }
        if(dval=="3")
        {
         txt.value="It's 3";
        }

    }
    </script>

Try the gridview below:

 <asp:GridView ID="GridView1" OnRowEditing="GridView1_RowEditing" OnRowUpdating="GridView1_RowUpdating"
                AutoGenerateColumns="false" OnRowCancelingEdit="GridView1_RowCancelingEdit" OnRowCommand="GridView1_RowCommand"
                runat="server" OnRowCreated="GridView1_RowCreated">
                <Columns>
                    <asp:CommandField ButtonType="link" ShowEditButton="true" ShowCancelButton="true" />
                    <asp:TemplateField HeaderText="CategoryID">
                        <ItemTemplate>
                            <asp:LinkButton ID="lnkID" runat="server" CommandName="sel" CommandArgument='<%# DataBinder.Eval(Container,"DataItem.CategoryID") %>'
                                Text='<%# DataBinder.Eval(Container,"DataItem.CategoryID") %>'></asp:LinkButton>
                        </ItemTemplate>
                        <EditItemTemplate>
                            <asp:DropDownList ID="ddl" runat="server">
                                <asp:ListItem Text="1" Value="1" Selected="true"></asp:ListItem>
                                <asp:ListItem Text="2" Value="2"></asp:ListItem>
                                <asp:ListItem Text="3" Value="3"></asp:ListItem>
                            </asp:DropDownList>
                        </EditItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="Comments">
                        <ItemTemplate>
                            <asp:Label ID="lblID" runat="server" Text='<%# DataBinder.Eval(Container,"DataItem.CategoryID") %>'></asp:Label>
                        </ItemTemplate>
                        <EditItemTemplate>
                            <asp:TextBox ID="txtComments" runat="server"></asp:TextBox>

                        </EditItemTemplate>
                    </asp:TemplateField>
                    <asp:TemplateField HeaderText="CategoryName">
                        <ItemTemplate>
                            <asp:LinkButton ID="lnkName" runat="server" CommandName="sel" CommandArgument='<%# DataBinder.Eval(Container,"DataItem.CategoryName") %>'
                                Text='<%# DataBinder.Eval(Container,"DataItem.CategoryName") %>'></asp:LinkButton>
                        </ItemTemplate>
                    </asp:TemplateField>
                </Columns>
            </asp:GridView>

Handle the rowcreated event in codebehind:

 protected void GridView1_RowCreated(object sender, GridViewRowEventArgs e)
    {
        if (e.Row.RowState == DataControlRowState.Edit)
        {
              DropDownList ddl = (DropDownList)e.Row.FindControl("ddl");
            TextBox txt = (TextBox)e.Row.FindControl("txtComments");
            txt.Text = "It's 1";
            //------------ Set onchange function for dropdown---------------------------//
            ddl.Attributes.Add("onchange", "javascript:ChangeValue(this,'" + txt.ClientID + "');");
        }
    }

Bind the grid with Categories table in northwind db.