[英]Populating a cascading dropdown on parent dropdown selection using jQuery
[英]Cascading dropdown not populating
我一直在遵循以下示例在Web應用程序中創建一些級聯下拉列表。 該示例不使用jquery,我現在想堅持使用它。 https://www.aspsnippets.com/Articles/Populate-Cascading-DropDownList-from-Database-in-ASPNet-Example.aspx
我無法使用第二個下拉列表中的第一個結果來填充列表。 這是我的代碼:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
CategorySelect.Items.Clear();
CategorySelect.Items.Add(new ListItem("--Select Activity--", ""));
CategorySelect.AppendDataBoundItems = true;
String strConnString = ConfigurationManager
.ConnectionStrings["iSAMSConnectionString"].ConnectionString;
String strQuery = "select TblActivityManagerFolderID, txtName from dbo.TblActivityManagerFolder";
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand();
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = con;
try
{
con.Open();
CategorySelect.DataSource = cmd.ExecuteReader();
CategorySelect.DataTextField = "txtName";
CategorySelect.DataValueField = "TblActivityManagerFolderID";
CategorySelect.DataBind();
}
finally
{
con.Close();
con.Dispose();
}
}
}
protected void ActivitySelect_SelectedIndexChanged(object sender, EventArgs e)
{
ActivitySelect.Items.Clear();
ActivitySelect.Items.Add(new ListItem("--Select Activity--", ""));
ActivitySelect.AppendDataBoundItems = true;
String strConnString = ConfigurationManager
.ConnectionStrings["iSAMSConnectionString"].ConnectionString;
String strQuery = "select txtName, TblActivityManagerGroupID from dbo.TblActivityManagerGroup " +
"where intFolder=@txtName";
SqlConnection con = new SqlConnection(strConnString);
SqlCommand cmd = new SqlCommand();
cmd.Parameters.AddWithValue("@txtName",
CategorySelect.SelectedItem.Value);
cmd.CommandType = CommandType.Text;
cmd.CommandText = strQuery;
cmd.Connection = con;
try
{
con.Open();
ActivitySelect.DataSource = cmd.ExecuteReader();
ActivitySelect.DataTextField = "txtName";
ActivitySelect.DataValueField = "TblActivityManagerGroupID";
ActivitySelect.DataBind();
if (ActivitySelect.Items.Count > 1)
{
ActivitySelect.Enabled = true;
}
else
{
ActivitySelect.Enabled = false;
}
}
finally
{
con.Close();
con.Dispose();
}
}
我正在使用2張桌子。
TblActivityManagerFolder這里我使用的2場-
TblActivityManagerFolderID
和txtName
TblActivityManagerGroup這里我使用的2場-
intFolder
(其連接到TblActivityManagerFolderID)和txtName
我的第一個下拉列表完全按預期填充,但是當我進行選擇時,第二個下拉列表中什么也沒有發生。
附加代碼:
<asp:SqlDataSource ID="iSAMS" runat="server" ConnectionString="<%$ ConnectionStrings:iSAMSConnectionString %>"
SelectCommand="SELECT [blnActive], [TblActivityManagerFolderID], [txtName] FROM [TblActivityManagerFolder] WHERE ([intActivity] = @intActivity)">
<SelectParameters>
<asp:Parameter DefaultValue="34" Name="intActivity" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>
</div>
<div class="auto-style18">
<asp:DropDownList ID="CategorySelect" runat="server" DataTextField="txtName" DataValueField="TblActivityManagerFolderID"
OnSelectedIndexChanged="ActivitySelect_SelectedIndexChanged" CssClass="newStyle1">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="CategorySelect"
ErrorMessage="Please select your answer" style="text-align: left; font-weight: 700; color: #FF0000; font-size: medium;">!</asp:RequiredFieldValidator>
</div>
<br />
<div class="auto-style19">
<div class="auto-style20">
Please select the activity undertaken from the pick list:
<asp:DropDownList ID="ActivitySelect" runat="server" DataSourceID="iSAMSActivity" DataTextField="txtName" DataValueField="TblActivityManagerGroupId" CssClass="newStyle1" OnSelectedIndexChanged="ActivitySelect_SelectedIndexChanged">
</asp:DropDownList>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="ActivitySelect"
ErrorMessage="Please select your answer" style="text-align: left; font-weight: 700; color: #FF0000; font-size: medium;">!</asp:RequiredFieldValidator>
<asp:SqlDataSource ID="iSAMSActivity" runat="server" ConnectionString="<%$ ConnectionStrings:iSAMSConnectionString %>" SelectCommand="SELECT [txtName], [intActivity], [intFolder], [TblActivityManagerGroupId] FROM [TblActivityManagerGroup] WHERE ([intFolder] = @intFolder)">
<SelectParameters>
<asp:ControlParameter ControlID="CategorySelect" Name="intFolder" PropertyName="SelectedValue" Type="Int32" />
</SelectParameters>
</asp:SqlDataSource>
我還回發了結果,因此我可以使用以下方法查看它是否在工作:
protected void Button1_Click(object sender, EventArgs e)
{
var activity = CategorySelect.DataTextField;
var CoCActivity = ActivitySelect.DataTextField;
var OtherSkills = SkillsTextBox.Text;
var ExtraDev = DevTextBox.Text;
var OtherActivities = OtherActivitiesTextBox.Text;
OutputLabel.Text = activity + "<br/>" + CoCActivity + "<br/>" + OtherSkills + "<br/>" + ExtraDev + "<br/>" + OtherActivities;
}
回發時,它會生成一個整數,而不是下拉列表中的標簽。 可以更改它以便回發實際文本嗎?
將AutoPostBack
屬性設置為True。 如果未設置,則僅當其他事件強制回發(單擊按鈕或類似操作)時,才在服務器端觸發該事件
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