Populate TextBox based on DateTime Field. ASP.NET C# JS

Question

Ok so I have a StartDate field:

<asp:TextBox ID="txtnewStartDate" runat="server" Text='<%# Bind("StartDate", "{0:MM/dd/yyyy}")%>'
                    CssClass="datepicker grid_5 text"></asp:TextBox>

I also have a TextBox which I would like to be auto filled based on the StartDate.

<asp:TextBox ID="txtDateBatch" Text='<%# Bind("DateBatch") %>' runat="server" CssClass="text"></asp:TextBox>

So for example the StartDate field will look like: 9/1/2015 (After a user has selected a date from the date box)

Now based on the date someone selected in this field the DateBatch field will look like: Batch-912015

I have seen an example using javascript but im not sure how to call the variables from javascript to asp or c#.

Javascript Ex:

<script type="text/javascript">
    function autoBatch() {
        value1 = $('#StartDate').val();
        var batch = "Batch-" + value1;
    }
</script>

Please let me know if I was not informative enough or anyone needs more info thanks! I don't need to use javascript whatever method works I would just like to understand how to do this from start to finish mainly confused on how to complete this fully.

Answer 1

Try adding an OnTextChanged event to the textbox, as below....

<asp:TextBox ID="txtnewStartDate" runat="server" OnTextChanged="txtnewStartDate_TextChanged" Text='<%# Bind("StartDate", "{0:MM/dd/yyyy}")%>' CssClass="datepicker grid_5 text"></asp:TextBox>

Then in your code behind, catch the value and update your DateBatch, as below....

protected void txtnewStartDate_TextChanged(object sender,EventArgs e)
    {

     txtDateBatch.Text = txtnewStartDate.Text

    }

Or with your batch code added.....

protected void txtnewStartDate_TextChanged(object sender,EventArgs e)
    {

     txtDateBatch.Text = "Batch-" & txtnewStartDate.Text.replace('/','')

    }

Something like that.