网格视图复选框已选中数据库值

Question

I get an error of

Specified cast is not valid

when I try to run my syntax. What I am wanting to do is if the value in the database is yes check the checkbox, if it is no, then do not check the checkbox. Here is my HTML that shows how I am trying to do such:

<asp:GridView runat="server" ID="dg123" AutoGenerateColumns="false" CssClass="DataGrids" GridLines="Both" ShowFooter="true">
<FooterStyle CssClass="DataGridFooters" /><HeaderStyle CssClass="DataGridHeaders" />
<Columns>
<asp:BoundField DataField="abc" HeaderText="Alpha" />
<asp:BoundField DataField="efg" HeaderText="Echo" />
<asp:TemplateField>
    <ItemTemplate><asp:CheckBox ID="Completed" runat="server" Checked='<%#Eval ("Completed") %>'/></ItemTemplate>
</asp:TemplateField>
</Columns>

Where in the example above, abc efg and Completed are all fields in the database.

Answer 1

You have to make following changes to make this work.

I am assuming that the data item Completed has a value of either yes or no .

1. Add following method to code-behind. This method returns a boolean value corresponding to string value of yes or no . This method must return a boolean type else you will get cast exception, since the property you are binding to ie Checked is of boolean type.

    public bool GetBoolValue(string val) { if (val.ToLower() == "yes") { return true; } else { return false; } return false; } 

2. In your markup, change the markup for checked box to what is given below.

    <ItemTemplate> <asp:CheckBox ID="Completed" runat="server" Checked='<%# GetBoolValue(Eval("Completed").ToString()) %>'/> </ItemTemplate>