无法执行'='系统操作.Int32和System.String"在执行搜索时

本文关键字：执行 quot String 搜索 System 操作 系统 Int32 | 更新日期: 2023-09-27 17:53:08

尝试搜索数据列表，参数为电影类型(通过数据库加载，因此没有切换情况)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();
        }
    }

试着调试，字符串本身似乎很好，所以我试着在过滤器上使用Convert.ToString()，只是为了确保，但这并不重要。帮助吗?

Thanks in advance

无法执行'='系统操作.Int32和System.String"在执行搜索时

这不是编译时错误，而是运行时错误。

在你的数据库中你要应用过滤器的对象是Int32..

例如，如果你有一个类似Num的东西，它是Int32的，但你做如下操作:-

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

会抛出错误，因为它需要:-

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

在你的例子中，你有GenreID，它是Int32的但是在你的代码中，你为它提供了一些字符串

可能您的GenreID列是INTEGER，您将其与'**'中的STRING进行比较。在这个示例中，我使用IN运算符一次列出所有值，它们之间没有AND运算符，这会导致逻辑错误，因为没有项具有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();
}

过滤器在你的条件可能是无效的，所以使用OR在AND的地方

在LIKE Operator

中使用%代替*

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

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 += " OR ";
                    filter+="'%"+this.CheckBoxListGenres.Items[i].Value.ToString()+"%'";
                    n++;
                }
            }
            if (this.TextBoxMovieName.Text!="")
                filter += " OR MovieName LIKE '%" + this.TextBoxMovieName.Text + "%'";
            DataTable dataTable = ((DataSet)Application["DataSetMovies"]).Tables[0];
            DataView dataView = new DataView(dataTable);
            filter = Convert.ToString(filter);
            dataView.RowFilter = filter;
            this.DataListMovies.DataSource = dataView;
            this.DataListMovies.DataBind();
        }
    }

DataRow filteredRows = dt.Select(“Name LIKE '%” + searchstring + “%’

或

convert(Age, System.String) like '%” + searchstring + “%'”);

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