将字符串插入vb.net中的数据绑定组合框中 [英] Inserting String into a databound combobox in vb.net

问题描述

大家好，

是否可以将字符串项插入从表填充的组合框中?

我的代码如下:

Hi all,

Is it possible to insert a string item into a combobox which is being populated from a table?

My code is as follows:

dim dv as dataview
dv = obj.get()
ddlReasons.DataSource = dv.Table
ddlReasons.DisplayMember = dv.Table.Columns("Reason").ToString
ddlReasons.ValueMember = dv.Table.Columns("Reason").ToString

我尝试放入

I tried putting in

ddlReasons.Items.Insert(0,"--Please Select--")

但组合框仍只显示它从表中检索到的项目.

谢谢.

but still the combobox only displays the items it retrieved from the table.

Thanks.

推荐答案

或类似的东西

Or Something Like This

ddlReasons.Items.Add("--Select---")

ddlReasons.DataSource = dv.Table
ddlReasons.DisplayMember = dv.Table.Columns("Reason").ToString
ddlReasons.ValueMember = dv.Table.Columns("Reason").ToString

尝试一下

dim dv as dataview
dv = obj.get()

      Dim dr As DataRow
      dr = dv.Table.NewRow()
      dr("ID") = 0
      dr("name") = "--Please Select--"
      dv.Table.Rows.InsertAt(dr, 0)
ddlReasons.DataSource = dv.Table
ddlReasons.DisplayMember = dv.Table.Columns("Reason").ToString
ddlReasons.ValueMember = dv.Table.Columns("Reason").ToString

每当我需要执行此操作时，我都会在查询级别执行.
它使我的代码最一致.
说我要填充下拉列表的查询是

Whenever I need to do this, I do it at the query level.
It makes my code most consistent.
Say my query to populate the dropdown is

Select name, id from myTable

我在上面添加了union子句.

I add a union clause to that.

Select name, id from myTable
Union
Select ''---Please Select---'', 0

.
通常可以.

.
That usually works.

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