更新Int32列获取“输入字符串的格式不正确”

Question

I've aa webform which update a db table, there is an error "Input string was not in a correct format" after submitted the form

nodeDetails.cs

protected void SqlDataSource_Updating(object sender, SqlDataSourceCommandEventArgs e)
{
    DropDownList ddl = (DropDownList)(DetailsView1.Rows[0].FindControl("DropDownList4"));
    DataRowView dr = (DataRowView)DetailsView1.DataItem;

    e.Command.Parameters["@parent_id"].Value = ddl.SelectedValue;

}

some code in nodeDetails.aspx

UpdateCommand="UPDATE [node] SET [title] = @title, [parent_id] = @parent_id, [oid] = @oid, [display] = @display, [linkById] = @linkById, [showContent] = @showContent, [customLinks] = @customLinks, [contentType] = @contentType WHERE [id] = @id"

    <UpdateParameters>
        <asp:Parameter Name="title" Type="String" />
        <asp:Parameter Name="parent_id" Type="Int32" />
        <asp:Parameter Name="oid" Type="Int32" />
        <asp:Parameter Name="display" Type="Byte" />
        <asp:Parameter Name="linkById" Type="Byte" />
        <asp:Parameter Name="showContent" Type="Byte" />
        <asp:Parameter Name="customLinks" Type="String" />
        <asp:Parameter Name="contentType" Type="String" />
        <asp:Parameter Name="id" Type="Int32" />
    </UpdateParameters>

The error will is caused by e.Command.Parameters["@parent_id"].Value = ddl.SelectedValue;

Anyone know what is the problem?

Answer 1

you need to make sure ddl.SelectedValue return correct integer value before setting parameter

DropDownList ddl = (DropDownList)(DetailsView1.Rows[0].FindControl("DropDownList4"));

int val;
if(int.TryParse(ddl.SelectedValue, out val)
{
   e.Command.Parameters["@parent_id"].Value = val;
}

when you bind DropDownList4 make integer field as value member of it.