c# - 更新パネルを追加した後、ドロップダウンリストが更新されない

Question

複数のドロップダウンリストボックスがあり、すべて同じ列、同じテーブル、同じデータベースからクエリを実行しています。たとえば、memberID 列の下に次の ID があります。

12345
23456
34567

そして、以下に示すように、3つの異なるドロップダウンリストボックスがあります

    <asp:DropDownList ID="memberID3" runat="server" Visible="false" OnSelectedIndexChanged="ddlpid3_SelectedIndexChanged" >
    </asp:DropDownList>
    <asp:DropDownList ID="memberID1" runat="server" Visible="false" OnSelectedIndexChanged="ddlpid1_SelectedIndexChanged">
    </asp:DropDownList>
    <asp:DropDownList ID="memberID2" runat="server" Visible="false" OnSelectedIndexChanged="ddlpid2_SelectedIndexChanged">
    </asp:DropDownList>

更新/選択時にドロップダウンリストを更新できるように、ドロップダウンリストの間に更新パネルを追加しました。

  <asp:UpdatePanel ID="UpdatePanel1" runat="server">
  <ContentTemplate>
  </ContentTemplate>
  </asp:UpdatePanel>

たとえば、memberID1 が 12345 を選択した場合、他の 2 つのドロップダウンリスト (memberID2 と 3) には ID 12345 が表示されません。すべての DDL にデフォルト値を追加しました。

 memeberID(number).Items.Insert(0, new ListItem(" Please select a Member ID", ""));
 memeberID(number).SelectedIndex = 0;

更新パネルのプロパティを間違えていなければ、この機能は動作しないのでしょうか?

要求されたバインディングコードは次のとおりです。

protected void ddllocation_SelectedIndexChanged(object sender, EventArgs e)
    {

        using (var connAdd = new SqlConnection("Data Source = localhost; Initial Catalog = MajorProject; Integrated Security= SSPI"))
        {
            connAdd.Open();

            var sql = "Select policeid from PoliceAccount where status ='available' and handle ='offcase' and postedto='" + ddllocation.SelectedValue + "'";
            using (var cmdAdd = new SqlDataAdapter(sql, connAdd))
            {
                DataSet ds2 = new DataSet();
                cmdAdd.Fill(ds2);

                memberID1.Items.Clear();
                memberID1.DataSource = ds2;
                memberID1.DataTextField = "memberID";
                memberID1.DataValueField = "memberID";
                memberID1.DataBind();
                memberID1.Items.Insert(0, new ListItem("Please select a Member ID", ""));
                memberID1.SelectedIndex = 0;

                memberID2.Items.Clear();
                memberID2.DataSource = ds2;
                memberID2.DataTextField = "memberID";
                memberID2.DataValueField = "memberID";
                memberID2.DataBind();
                memberID2.Items.Insert(0, new ListItem("Please select a Member ID", ""));
                memberID2.SelectedIndex = 0;

                memberID3.Items.Clear();
                memberID3.DataSource = ds2;
                memberID3.DataTextField = "memberID";
                memberID3.DataValueField = "memberID";
                memberID3.DataBind();
                memberID3.Items.Insert(0, new ListItem("Please select a Member ID", ""));
                memberID3.SelectedIndex = 0;



            }

アップデート

今のところ、デフォルト値が選択されているときに、他のドロップダウンリストで選択した値を他の ddl が再バインドしてキャッシュできるようにすることができます。ただし、他の ID を選択すると、ID が削除され、他の ddl を再バインドしません。

protected void FillddlLocations()
    {
        FillDropdown(ddlpid1);
        FillDropdown(ddlpid2);
        FillDropdown(ddlpid3);
        FillDropdown(ddlpid4);
        FillDropdown(ddlpid5);
        ddlpid1.Visible = false;
        ddlpid2.Visible = false;
        ddlpid3.Visible = false;
        ddlpid4.Visible = false;
        ddlpid5.Visible = false;
    }

    protected void FillDropdown(DropDownList ddl)
    {

        using (var connAdd = new SqlConnection("Data Source = localhost; Initial Catalog = MajorProject; Integrated Security= SSPI"))
        {
            connAdd.Open();

            var sql = "Select policeid from PoliceAccount where status ='available' and handle ='offcase' and postedto='" + ddllocation.SelectedValue + "'";
            using (var cmdAdd = new SqlDataAdapter(sql, connAdd))
            {
                DataSet ds2 = new DataSet();
                cmdAdd.Fill(ds2);

                ddl.Items.Clear();
                ddl.DataSource = ds2;
                ddl.DataBind();
                ddl.Items.Insert(0, new ListItem("Police ID", ""));
                ddl.SelectedIndex = 0;

            }

        }
    }

    protected void ddlpid1_SelectedIndexChanged(object sender, EventArgs e)
    {

        if (ddlpid1.SelectedIndex > 0)
        {

            Session["pid1"] = ddlpid1.SelectedValue;

            ListItem removeItem2 = ddlpid2.Items.FindByValue(ddlpid1.SelectedValue);
            ddlpid2.Items.Remove(removeItem2);
            ListItem removeItem3 = ddlpid3.Items.FindByValue(ddlpid1.SelectedValue);
            ddlpid3.Items.Remove(removeItem3);
            ListItem removeItem4 = ddlpid4.Items.FindByValue(ddlpid1.SelectedValue);
            ddlpid4.Items.Remove(removeItem4);
            ListItem removeItem5 = ddlpid5.Items.FindByValue(ddlpid1.SelectedValue);
            ddlpid5.Items.Remove(removeItem5);


        }

        else

        if (ddlpid1.SelectedItem.Text.Equals("Police ID"))
        {
            FillDropdown(ddlpid1);
            FillDropdown(ddlpid2);
            FillDropdown(ddlpid3);
            FillDropdown(ddlpid4);
            FillDropdown(ddlpid5);


            ddlpid2.SelectedValue = (String)Session["pid2"];
            ddlpid2_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid3.SelectedValue = (String)Session["pid3"];
            ddlpid3_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid4.SelectedValue = (String)Session["pid4"];
            ddlpid4_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid5.SelectedValue = (String)Session["pid5"];
            ddlpid5_SelectedIndexChanged(this, EventArgs.Empty);
        }





    }

    protected void ddlpid2_SelectedIndexChanged(object sender, EventArgs e)
    {

        if (ddlpid2.SelectedIndex > 0)
        {

            Session["pid2"] = ddlpid2.SelectedValue;
            ListItem removeItem1 = ddlpid1.Items.FindByValue(ddlpid2.SelectedValue);
            ddlpid1.Items.Remove(removeItem1);
            ListItem removeItem3 = ddlpid3.Items.FindByValue(ddlpid2.SelectedValue);
            ddlpid3.Items.Remove(removeItem3);
            ListItem removeItem4 = ddlpid4.Items.FindByValue(ddlpid2.SelectedValue);
            ddlpid4.Items.Remove(removeItem4);
            ListItem removeItem5 = ddlpid5.Items.FindByValue(ddlpid2.SelectedValue);
            ddlpid5.Items.Remove(removeItem5);


        }
        else if (ddlpid2.SelectedItem.Text.Equals("Police ID"))
        {
            FillDropdown(ddlpid1);
            FillDropdown(ddlpid2);
            FillDropdown(ddlpid3);
            FillDropdown(ddlpid4);
            FillDropdown(ddlpid5);

            ddlpid1.SelectedValue = (String)Session["pid1"];
            ddlpid1_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid3.SelectedValue = (String)Session["pid3"];
            ddlpid3_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid4.SelectedValue = (String)Session["pid4"];
            ddlpid4_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid5.SelectedValue = (String)Session["pid5"];
            ddlpid5_SelectedIndexChanged(this, EventArgs.Empty);
        }


    }   

    protected void ddlpid3_SelectedIndexChanged(object sender, EventArgs e)
    {          
        if (ddlpid3.SelectedIndex > 0)
        {

            Session["pid3"] = ddlpid3.SelectedValue;
            ListItem removeItem1 = ddlpid1.Items.FindByValue(ddlpid3.SelectedValue);
            ddlpid1.Items.Remove(removeItem1);
            ListItem removeItem2 = ddlpid2.Items.FindByValue(ddlpid3.SelectedValue);
            ddlpid2.Items.Remove(removeItem2);
            ListItem removeItem4 = ddlpid4.Items.FindByValue(ddlpid3.SelectedValue);
            ddlpid4.Items.Remove(removeItem4);
            ListItem removeItem5 = ddlpid5.Items.FindByValue(ddlpid3.SelectedValue);
            ddlpid5.Items.Remove(removeItem5);


        }   
    else if (ddlpid3.SelectedItem.Text.Equals("Police ID"))
        {
            FillDropdown(ddlpid1);
            FillDropdown(ddlpid2);
            FillDropdown(ddlpid3);
            FillDropdown(ddlpid4);
            FillDropdown(ddlpid5);

            ddlpid1.SelectedValue = (String)Session["pid1"];
            ddlpid1_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid2.SelectedValue = (String)Session["pid2"];
            ddlpid2_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid4.SelectedValue = (String)Session["pid4"];
            ddlpid4_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid5.SelectedValue = (String)Session["pid5"];
            ddlpid5_SelectedIndexChanged(this, EventArgs.Empty);
        }


    }

    protected void ddlpid4_SelectedIndexChanged(object sender, EventArgs e)
    {            
        if (ddlpid4.SelectedIndex > 0)
        {
            Session["pid4"] = ddlpid4.SelectedValue;

            ListItem removeItem1 = ddlpid1.Items.FindByValue(ddlpid4.SelectedValue);
            ddlpid1.Items.Remove(removeItem1);
            ListItem removeItem2 = ddlpid2.Items.FindByValue(ddlpid4.SelectedValue);
            ddlpid2.Items.Remove(removeItem2);
            ListItem removeItem3 = ddlpid3.Items.FindByValue(ddlpid4.SelectedValue);
            ddlpid3.Items.Remove(removeItem3);
            ListItem removeItem5 = ddlpid5.Items.FindByValue(ddlpid4.SelectedValue);
            ddlpid5.Items.Remove(removeItem5);


        }

        else if (ddlpid4.SelectedItem.Text.Equals("Police ID"))
        {


            FillDropdown(ddlpid1);
            FillDropdown(ddlpid2);
            FillDropdown(ddlpid3);
            FillDropdown(ddlpid4);
            FillDropdown(ddlpid5);

            ddlpid1.SelectedValue = (String)Session["pid1"];
            ddlpid1_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid2.SelectedValue = (String)Session["pid2"];
            ddlpid2_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid3.SelectedValue = (String)Session["pid3"];
            ddlpid3_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid5.SelectedValue = (String)Session["pid5"];
            ddlpid5_SelectedIndexChanged(this, EventArgs.Empty);
        }


    }       

    protected void ddlpid5_SelectedIndexChanged(object sender, EventArgs e)
    {           

        if (ddlpid5.SelectedIndex > 0)
        {

            Session["pid5"] = ddlpid5.SelectedValue;
            ListItem removeItem1 = ddlpid1.Items.FindByValue(ddlpid5.SelectedValue);
            ddlpid1.Items.Remove(removeItem1);
            ListItem removeItem2 = ddlpid2.Items.FindByValue(ddlpid5.SelectedValue);
            ddlpid2.Items.Remove(removeItem2);
            ListItem removeItem3 = ddlpid3.Items.FindByValue(ddlpid5.SelectedValue);
            ddlpid3.Items.Remove(removeItem3);
            ListItem removeItem4 = ddlpid4.Items.FindByValue(ddlpid5.SelectedValue);
            ddlpid4.Items.Remove(removeItem4);

        }

    else if (ddlpid5.SelectedItem.Text.Equals("Police ID"))
        {
            FillDropdown(ddlpid1);
            FillDropdown(ddlpid2);
            FillDropdown(ddlpid3);
            FillDropdown(ddlpid4);
            FillDropdown(ddlpid5);

            ddlpid1.SelectedValue = (String)Session["pid1"];
            ddlpid1_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid2.SelectedValue = (String)Session["pid2"];
            ddlpid2_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid3.SelectedValue = (String)Session["pid3"];
            ddlpid3_SelectedIndexChanged(this, EventArgs.Empty);

            ddlpid4.SelectedValue = (String)Session["pid4"];
            ddlpid4_SelectedIndexChanged(this, EventArgs.Empty);
        }

    }

score 1 · Accepted Answer

まず、マークアップでドロップダウンのAutoPostBackプロパティを true に設定します。

<asp:DropDownList ID="memberID1" AutoPostBack="true" runat="server" Visible="false" OnSelectedIndexChanged="ddlpid1_SelectedIndexChanged">
    </asp:DropDownList>
    <asp:DropDownList ID="memberID2" AutoPostBack="true" runat="server" Visible="false" OnSelectedIndexChanged="ddlpid2_SelectedIndexChanged">
    </asp:DropDownList>
    <asp:DropDownList ID="memberID3" AutoPostBack="true" runat="server" Visible="false" OnSelectedIndexChanged="ddlpid3_SelectedIndexChanged" >
    </asp:DropDownList>

更新: 選択した値をビューステートに保存し、以下のようにドロップダウンリストを再設定した後に取得できます。

public partial class WebForm2 : System.Web.UI.Page
{
    bool bFlag = true;

    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            FillddlLocations();
        }
    }

    //Properties to store selected value in ViewState

    protected string MemberID1Selection
    {
        get
        {
            if (ViewState["MemberID1Selection"] != null)
                return ViewState["MemberID1Selection"].ToString();
            return "";
        }
        set { ViewState["MemberID1Selection"] = value; }
    }

    protected string MemberID2Selection
    {
        get
        {
            if (ViewState["MemberID2Selection"] != null)
                return ViewState["MemberID2Selection"].ToString();
            return "";
        }
        set { ViewState["MemberID2Selection"] = value; }
    }

    protected string MemberID3Selection
    {
        get
        {
            if (ViewState["MemberID3Selection"] != null)
                return ViewState["MemberID3Selection"].ToString();
            return "";
        }
        set { ViewState["MemberID3Selection"] = value; }
    }


    protected void FillddlLocations()
    {
        FillDropdown(memberID1);
        FillDropdown(memberID2);
        FillDropdown(memberID3);
        memberID1.Visible = true;
        memberID2.Visible = true;
        memberID3.Visible = true;
    }

    protected void FillDropdown(DropDownList ddl)
    {

        using (var connAdd = new SqlConnection("Data Source = localhost; Initial Catalog = MajorProject; Integrated Security= SSPI"))
        {
            connAdd.Open();

            var sql = "Select policeid from PoliceAccount where status ='available' and handle ='offcase' and postedto='" + ddllocation.SelectedValue + "'";
            using (var cmdAdd = new SqlDataAdapter(sql, connAdd))
            {
                DataSet ds2 = new DataSet();
                cmdAdd.Fill(ds2);


                ddl.Items.Clear();
                ddl.DataSource = ds2;
                ddl.DataTextField = "memberID";
                ddl.DataValueField = "memberID";
                ddl.DataBind();
                ddl.Items.Insert(0, new ListItem("Please select a Member ID", ""));
                ddl.SelectedIndex = 0;

            }

        }
    }

    protected void IndexChanged(DropDownList ddlChanged, DropDownList ddlToFilter1, DropDownList ddlToFilter2)
    {
        string removeValue1 = ddlChanged == memberID1 ? MemberID1Selection : (ddlChanged == memberID2 ? MemberID2Selection : MemberID3Selection);
        string selValue2 = ddlChanged == memberID1 ? MemberID2Selection : (ddlChanged == memberID2 ? MemberID1Selection : MemberID1Selection);
        string selValue3 = ddlChanged == memberID1 ? MemberID3Selection : (ddlChanged == memberID2 ? MemberID3Selection : MemberID2Selection);

        bFlag = false;//Prevent fireing the code again while changing the index
        if (removeValue1 != "")
        {
            ListItem item1 = ddlToFilter1.Items.FindByValue(removeValue1);
            ddlToFilter1.Items.Remove(item1);
            ListItem item2 = ddlToFilter2.Items.FindByValue(removeValue1);
            ddlToFilter2.Items.Remove(item2);            
        }

        if (selValue3 != "")
        {
            ListItem item3 = ddlToFilter1.Items.FindByValue(selValue3);
            ddlToFilter1.Items.Remove(item3);
        }
        if (selValue2 != "")
        {
            ListItem item4 = ddlToFilter2.Items.FindByValue(selValue2);
            ddlToFilter2.Items.Remove(item4);
        }

        bFlag = false;
        ddlToFilter1.SelectedIndex = ddlToFilter1.Items.IndexOf(ddlToFilter1.Items.FindByValue(selValue2));
        ddlToFilter2.SelectedIndex = ddlToFilter2.Items.IndexOf(ddlToFilter2.Items.FindByValue(selValue3));
    }

    protected void ddlpid1_SelectedIndexChanged(object sender, EventArgs e)
    {
        MemberID1Selection = memberID1.SelectedValue;
        if (bFlag)
        {
            FillDropdown(memberID2);
            FillDropdown(memberID3);
            IndexChanged(memberID1, memberID2, memberID3);
        }
    }

    protected void ddlpid2_SelectedIndexChanged(object sender, EventArgs e)
    {
        MemberID2Selection = memberID2.SelectedValue;
        if (bFlag)
        {
            FillDropdown(memberID1);
            FillDropdown(memberID3);
            IndexChanged(memberID2, memberID1, memberID3);
        }
    }
    protected void ddlpid3_SelectedIndexChanged(object sender, EventArgs e)
    {
        MemberID3Selection = memberID3.SelectedValue;
        if (bFlag)
        {
            FillDropdown(memberID1);
            FillDropdown(memberID2);
            IndexChanged(memberID3, memberID1, memberID2);
        }
    }
}

私はコードをテストしましたが、それは私のために働いています。それが役に立てば幸い！

c# - 更新パネルを追加した後、ドロップダウンリストが更新されない

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