“执行搜索时,无法对System.Int32和System.String执行'='操作”

时间:2015-06-04 08:05:43

标签: c# .net-3.5

尝试搜索DataList,参数为电影类型(通过数据库加载,因此没有切换案例)和名称

protected void ButtonFilter_Click(object sender, EventArgs e)
    {
        string filter = "";
        int selectedCount = 0;
        for (int i = 0; i < this.CheckBoxListGenres.Items.Count; i++)
            if (this.CheckBoxListGenres.Items[i].Selected)
                selectedCount++;
        if (selectedCount > 0)
        {
            filter = "GenreID=";
            int n = 0; //Used to determine to which genre the loop has arrived
            for (int i = 0; i < this.CheckBoxListGenres.Items.Count; i++)
            {
                if (this.CheckBoxListGenres.Items[i].Selected)
                {
                    if (n > 0 && n < selectedCount)
                        filter += " AND ";
                    filter+="'*"+this.CheckBoxListGenres.Items[i].Value.ToString()+"*'";
                    n++;

                }
            }

            if (this.TextBoxMovieName.Text!="")
                filter += " AND MovieName LIKE '*" + this.TextBoxMovieName.Text + "*'";
            DataTable dataTable = ((DataSet)Application["DataSetMovies"]).Tables[0];
            DataView dataView = new DataView(dataTable);
            filter = Convert.ToString(filter);
            dataView.RowFilter = filter; //!Getting the error here!
            this.DataListMovies.DataSource = dataView;
            this.DataListMovies.DataBind();
        }
    }

尝试调试,字符串本身似乎很好,所以我尝试在过滤器上使用Convert.ToString(),只是为了确保但无关紧要。 帮助

提前致谢

3 个答案:

答案 0 :(得分:10)

这不是编译时错误,这是运行时错误。

在您的数据库中,您要应用过滤器的东西是Int32 ..

的类型

例如,如果你有类似Num的内容,而且它是Int32,但你会做如下事情: -

dv.RowFilter = "Num = '7097'" ////This will have error

它会抛出错误,因为它需要: -

dv.RowFilter = "Num = 7097" ////This is correct

所以在你的情况下,你有GenreID是Int32,但在你的代码中你提供了一些字符串。

答案 1 :(得分:1)

您的GenreID列可能是INTEGER,您可以将其与STRING中的'**'进行比较。在这个示例中,我使用IN运算符一次列出所有值,而它们之间没有AND运算符,什么会导致逻辑错误,因为没有项目会有GenreID = 1和GenreID = 2:

protected void ButtonFilter_Click(object sender, EventArgs e)
{
    string filter = "1=1";
    if (this.CheckBoxListGenres.Items.OfType<ListItem>().Any(i => i.Selected))
        filter += String.Format(" AND GenreID IN ({0})'",
            String.Join(",", this.CheckBoxListGenres.Items.OfType<ListItem>()
                .Where(i => i.Selected).Select(i => i.Value)));

    if (this.TextBoxMovieName.Text != "")
        filter += " AND MovieName LIKE '%" + this.TextBoxMovieName.Text + "%'";

    DataTable dataTable = ((DataSet)MediaTypeNames.Application["DataSetMovies"]).Tables[0];
    DataView dataView = new DataView(dataTable);
    dataView.RowFilter = filter;
    DataListMovies.DataSource = dataView;
    DataListMovies.DataBind();
}

答案 2 :(得分:0)

根据您的情况过滤可能无效,因此请在OR

的地方使用AND
  

%运营商

中使用*的{​​{1}}      

I.E LIKE

filter += " AND MovieName LIKE '%" + this.TextBoxMovieName.Text + "%'";