动态生成下拉列表web控件隐藏在选定的
本文关键字：隐藏 控件 下拉列表 web 动态 | 更新日期: 2023-09-27 18:01:37
我在创建动态web控件时遇到了麻烦。我有一个SQL databoundeddownlist与DataTextField ="All_Columns"和DataValueField="DATA_TYPE"。
在DropDownList1_SelectedIndexChanged上，我必须检查所选值的数据类型是十进制还是Varchar。如果它是十进制，我必须调用createddynamicwebcontrols_decimal()并创建DropDownList2。如果它是varchar，我必须调用createddynamicwebcontrols_varchar()。
当前问题:在DropDownList2_SelectedIndexChanged上，我必须创建两个动态文本框和输入值必须保留，并在JQGrid中搜索和显示数据与按钮单击事件的帮助。但是DDL控件完全隐藏了
如何实现以上所有功能。请帮忙。新的动态web控件。
Aspx代码:
<asp:DropDownList ID="DropDownList5" runat="server" DataSourceID="column_list_for_filter" DataTextField="All_Columns" DataValueField="DATA_TYPE" OnSelectedIndexChanged ="DropDownList5_SelectedIndexChanged" AutoPostBack="true" >
</asp:DropDownList>
<asp:SqlDataSource ID="column_list_for_filter" runat="server" ConnectionString="<%$ ConnectionStrings:DatabaseConnectionString %>" SelectCommand="SELECT COLUMN_NAME AS 'All_Columns', DATA_TYPE FROM INFORMATION_SCHEMA.COLUMNS WHERE (TABLE_NAME = 'TABLE')"></asp:SqlDataSource>
protected void Page_Load(object sender, EventArgs e)
{
Panel6.Visible = false;
JQGrid9.Visible = false;
if (Session["DataforSearch"] != null)
{
Panel6.Visible = true;
JQGrid9.Visible = true;
JQGrid9.DataSource = Session["DataforSearch"] as string;
}
}
protected void Page_PreInit(object sender, EventArgs e)
{
//How to Proceed
}
protected void DropDownList5_SelectedIndexChanged(object sender, EventArgs e)
{
if(DropDownList5.SelectedValue == "decimal")
{
createdynamiccontrols_decimal();
}
else if(DropDownList5.SelectedValue == "int")
{
createdynamiccontrols_int();
}
else if(DropDownList5.SelectedValue == "varchar")
{
createdynamiccontrols_varchar();
}
//How to Proceed
}
protected void createdynamiccontrols_decimal()
{
int i = DropDownList5.SelectedIndex;
++i;
TableRow row;
row = new TableRow();
TableCell cell1;
cell1 = new TableCell();
//DropDownList2
DropDownList Range_DDL;
Range_DDL = new DropDownList();
Range_DDL.ID = "RandeDDL" + i.ToString();
Range_DDL.Items.Insert(0, new ListItem("--Select--", "--Select--"));
Range_DDL.Items.Insert(1, new ListItem("Equal", "Equal"));
Range_DDL.Items.Insert(2, new ListItem("NotEqual", "NotEqual"));
Range_DDL.Items.Insert(3, new ListItem("greater than", "greater than"));
Range_DDL.Items.Insert(2, new ListItem("lesser than", "lesser than"));
Range_DDL.Items.Insert(2, new ListItem("greater than or equal to", "greater than or equal to"));
Range_DDL.Items.Insert(2, new ListItem("lesser than or equal to", "lesser than or equal to"));
Range_DDL.Items.Insert(2, new ListItem("Contains", "Contains"));
Range_DDL.Items.Insert(2, new ListItem("Is Null", "Is Null"));
Range_DDL.Items.Insert(2, new ListItem("Is Not Null", "Is Not Null"));
Range_DDL.Items.Insert(2, new ListItem("Between", "Between"));
Range_DDL.AutoPostBack = true;
Range_DDL.SelectedIndexChanged += new System.EventHandler(Range_DDL_SelectedIndexChanged);
cell1.Controls.Add(Range_DDL);
//// Add the TableCell to the TableRow
row.Cells.Add(cell1);
dynamic_filter_table.Rows.Add(row);
dynamic_filter_table.EnableViewState = true;
ViewState["dynamic_filter_table"] = true;
}
//DropdownList2 to create dynamic text boxes
protected void Range_DDL_SelectedIndexChanged(object sender, EventArgs e)
{
int j = DropDownList5.SelectedIndex;
++j;
TableRow row;
row = new TableRow();
TableRow rowtwo;
rowtwo = new TableRow();
TableCell cell1;
cell1 = new TableCell();
TableCell cell2;
cell2 = new TableCell();
TableCell cell3;
cell3 = new TableCell();
TextBox tb1;
tb1 = new TextBox();
TextBox tb2;
tb2 = new TextBox();
Label lbl1;
lbl1 = new Label();
Label lbl2;
lbl2 = new Label();
//// Set a unique ID for each TextBox added
tb1.ID = "lowerbound_" + j.ToString();
tb2.ID = "upperbound_" + j.ToString();
lbl1.Text = "LowerBound:";
lbl1.Font.Size = FontUnit.Point(10);
lbl1.Font.Bold = true;
lbl1.Font.Name = "Arial";
lbl2.Text = "UpperBound:";
lbl2.Font.Size = FontUnit.Point(10);
lbl2.Font.Bold = true;
lbl2.Font.Name = "Arial";
Button addmore;
addmore = new Button();
addmore.ID = "Button" + j.ToString();
addmore.Text = "+";
addmore.Click += new System.EventHandler(addmore_click);
cell1.Controls.Add(lbl1);
cell2.Controls.Add(tb1);
cell2.Controls.Add(lbl2);
cell2.Controls.Add(tb2);
cell3.Controls.Add(addmore);
row.Cells.Add(cell1);
row.Cells.Add(cell2);
rowtwo.Cells.Add(cell3);
dynamic_filter_table.Rows.Add(row);
dynamic_filter_table.EnableViewState = true;
ViewState["dynamic_filter_table"] = true;
}
//Button Click to retrieve the input from dynamic generated text box and display in JQGrid.
protected void Button1_Click(object sender, EventArgs e)
{
int j = DropDownList5.SelectedIndex;
++j;
Panel6.Visible = true;
JQGrid9.Visible = true;
TextBox lowerboundd = dynamic_filter_table.FindControl("lowerbound_" + j.ToString()) as TextBox;
TextBox upperbound = dynamic_filter_table.FindControl("upperbound_" + j.ToString()) as TextBox;
con.Open();
SqlDataAdapter da = new SqlDataAdapter("SELECT a,b,c FROM TABLE WHERE " + DropDownList5.SelectedValue + " >= " + lowerboundd.Text + " AND " + DropDownList5.SelectedValue + " <= " + upperbound.Text, con);
**//Problems in retrieving the input of textboxes - Object Reference error**
DataSet ds = new DataSet();
da.Fill(ds);
con.Close();
Session["DataforSearch"] = ds.Tables[0];
}
您可以在以下链接找到源代码和示例:http://www.codeproject.com/Articles/20714/Dynamic-ASP-NET-control-creation-using-C
我也在网上找到了这个代码，我希望它能对你有所帮助:你可以根据你的需要在这个代码中修改这个按钮是在点击另一个按钮时添加的。
给表单添加一个新控件真的很容易。
你所要做的就是像其他类一样创建一个控件的新实例。如:
Button NewButton = new button();
然后填写控件的属性。
NewButton.Text = "My New Button";
在此设置之后一个事件处理程序。
NewButton.Click += new EventHandler(NewButton_Click);
然后在按钮处理程序中使用sender参数来告诉您按下了哪个动态按钮。
void NewButton_Click(object sender, EventArgs e)
{
Button CurrentButton = (Button)sender;
CurrentButton.Text = "I was clicked";
}
设置按钮的最后一步是将控件添加到表单中。
this.Controls.Add(NewButton);