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POPicking category from one dropdownlist to show sub categories in another dropdownlist
 

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  1. POPicking category from one dropdownlist to show sub categories in another dropdownlist
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    <p>Im trying to make a dropdownlist control another via C#. My plan is, that the first DropDownList shows categories such as "Size" "Gender" "Model" and when you pick one of those, a new DropDownList shall appear with new sub categories for the former chosen category.</p> <p>For example, if I pick "Size" a new DropDownList shal appear, with the option to choose from a number of sizes.</p> <p>Im getting an error, while testing which sounds like this: Make sure your method arguments are in right format.</p> <p>Here is what my code looks like:</p> <pre><code>using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; using ContactTableAdapters; public partial class Test : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { } protected void ddlTwo_SelectedIndexChanged(object sender, EventArgs e) { ddlTwo.Items.Clear(); if (ddlThree.SelectedValue != "0") { Contact.CategoriesDataTable table; ddlTwo.AppendDataBoundItems = true; ddlTwo.Items.Add(new ListItem("Choose", "0")); CategoriesTableAdapter subM = new CategoriesTableAdapter(); int CategoryID = Convert.ToInt32(ddlThree.SelectedValue); //This is where I get the error table = subM.GetCategoryByCategoryID(CategoryID); foreach (Contact.CategoriesRow row in table) { string text = row.Category; string value = row.CategoryID.ToString(); ddlTwo.Items.Add(new ListItem(text, value)); } } } } </code></pre> <p>Can someone tell me, what I might have done wrong?</p>
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    1. USKasper Storgaard Kristensen
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    1. PO
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    1. COPlease debug and see what ddlThree.SelectedValue actually is. My guess is null...
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      1. POPicking category from one dropdownlist to show sub categories in another dropdownlist
      1. USStefan H
    2. CO"Input string was not in correct format" it says.
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      1. POPicking category from one dropdownlist to show sub categories in another dropdownlist
      1. USKasper Storgaard Kristensen
    3. COThat is the value of the exception message, correct? I need to know what the value of ddlThree.SelectedValue) is
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      1. POPicking category from one dropdownlist to show sub categories in another dropdownlist
      1. USStefan H
 

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